SQLAlchemy 2.0 Documentation
SQLAlchemy Core
- SQL Statements and Expressions API
- Column Elements and Expressions¶
- Column Element Foundational Constructors
- Column Element Modifier Constructors
- Column Element Class Documentation
BinaryExpression
BindParameter
Case
Cast
ClauseList
ColumnClause
ColumnCollection
ColumnCollection.add()
ColumnCollection.as_readonly()
ColumnCollection.clear()
ColumnCollection.compare()
ColumnCollection.contains_column()
ColumnCollection.corresponding_column()
ColumnCollection.get()
ColumnCollection.items()
ColumnCollection.keys()
ColumnCollection.update()
ColumnCollection.values()
ColumnElement
ColumnElement.__eq__()
ColumnElement.__le__()
ColumnElement.__lt__()
ColumnElement.__ne__()
ColumnElement.all_()
ColumnElement.allows_lambda
ColumnElement.anon_key_label
ColumnElement.anon_label
ColumnElement.any_()
ColumnElement.asc()
ColumnElement.base_columns
ColumnElement.between()
ColumnElement.bitwise_and()
ColumnElement.bitwise_lshift()
ColumnElement.bitwise_not()
ColumnElement.bitwise_or()
ColumnElement.bitwise_rshift()
ColumnElement.bitwise_xor()
ColumnElement.bool_op()
ColumnElement.cast()
ColumnElement.collate()
ColumnElement.comparator
ColumnElement.compare()
ColumnElement.compile()
ColumnElement.concat()
ColumnElement.contains()
ColumnElement.desc()
ColumnElement.description
ColumnElement.distinct()
ColumnElement.endswith()
ColumnElement.entity_namespace
ColumnElement.expression
ColumnElement.foreign_keys
ColumnElement.get_children()
ColumnElement.icontains()
ColumnElement.iendswith()
ColumnElement.ilike()
ColumnElement.in_()
ColumnElement.inherit_cache
ColumnElement.is_()
ColumnElement.is_clause_element
ColumnElement.is_distinct_from()
ColumnElement.is_dml
ColumnElement.is_not()
ColumnElement.is_not_distinct_from()
ColumnElement.is_selectable
ColumnElement.isnot()
ColumnElement.isnot_distinct_from()
ColumnElement.istartswith()
ColumnElement.key
ColumnElement.label()
ColumnElement.like()
ColumnElement.match()
ColumnElement.negation_clause
ColumnElement.not_ilike()
ColumnElement.not_in()
ColumnElement.not_like()
ColumnElement.notilike()
ColumnElement.notin_()
ColumnElement.notlike()
ColumnElement.nulls_first()
ColumnElement.nulls_last()
ColumnElement.nullsfirst()
ColumnElement.nullslast()
ColumnElement.op()
ColumnElement.operate()
ColumnElement.params()
ColumnElement.primary_key
ColumnElement.proxy_set
ColumnElement.regexp_match()
ColumnElement.regexp_replace()
ColumnElement.reverse_operate()
ColumnElement.self_group()
ColumnElement.shares_lineage()
ColumnElement.startswith()
ColumnElement.stringify_dialect
ColumnElement.supports_execution
ColumnElement.timetuple
ColumnElement.type
ColumnElement.unique_params()
ColumnElement.uses_inspection
ColumnExpressionArgument
ColumnOperators
ColumnOperators.__add__()
ColumnOperators.__and__()
ColumnOperators.__eq__()
ColumnOperators.__floordiv__()
ColumnOperators.__ge__()
ColumnOperators.__getitem__()
ColumnOperators.__gt__()
ColumnOperators.__hash__()
ColumnOperators.__invert__()
ColumnOperators.__le__()
ColumnOperators.__lshift__()
ColumnOperators.__lt__()
ColumnOperators.__mod__()
ColumnOperators.__mul__()
ColumnOperators.__ne__()
ColumnOperators.__neg__()
ColumnOperators.__or__()
ColumnOperators.__radd__()
ColumnOperators.__rfloordiv__()
ColumnOperators.__rmod__()
ColumnOperators.__rmul__()
ColumnOperators.__rshift__()
ColumnOperators.__rsub__()
ColumnOperators.__rtruediv__()
ColumnOperators.__sa_operate__()
ColumnOperators.__sub__()
ColumnOperators.__truediv__()
ColumnOperators.all_()
ColumnOperators.any_()
ColumnOperators.asc()
ColumnOperators.between()
ColumnOperators.bitwise_and()
ColumnOperators.bitwise_lshift()
ColumnOperators.bitwise_not()
ColumnOperators.bitwise_or()
ColumnOperators.bitwise_rshift()
ColumnOperators.bitwise_xor()
ColumnOperators.bool_op()
ColumnOperators.collate()
ColumnOperators.concat()
ColumnOperators.contains()
ColumnOperators.desc()
ColumnOperators.distinct()
ColumnOperators.endswith()
ColumnOperators.icontains()
ColumnOperators.iendswith()
ColumnOperators.ilike()
ColumnOperators.in_()
ColumnOperators.is_()
ColumnOperators.is_distinct_from()
ColumnOperators.is_not()
ColumnOperators.is_not_distinct_from()
ColumnOperators.isnot()
ColumnOperators.isnot_distinct_from()
ColumnOperators.istartswith()
ColumnOperators.like()
ColumnOperators.match()
ColumnOperators.not_ilike()
ColumnOperators.not_in()
ColumnOperators.not_like()
ColumnOperators.notilike()
ColumnOperators.notin_()
ColumnOperators.notlike()
ColumnOperators.nulls_first()
ColumnOperators.nulls_last()
ColumnOperators.nullsfirst()
ColumnOperators.nullslast()
ColumnOperators.op()
ColumnOperators.operate()
ColumnOperators.regexp_match()
ColumnOperators.regexp_replace()
ColumnOperators.reverse_operate()
ColumnOperators.startswith()
ColumnOperators.timetuple
Extract
False_
FunctionFilter
Label
Null
Operators
Over
SQLColumnExpression
TextClause
TryCast
Tuple
WithinGroup
WrapsColumnExpression
True_
TypeCoerce
UnaryExpression
- Column Element Typing Utilities
- Operator Reference
- SELECT and Related Constructs
- Insert, Updates, Deletes
- SQL and Generic Functions
- Custom SQL Constructs and Compilation Extension
- Expression Serializer Extension
- SQL Expression Language Foundational Constructs
- Visitor and Traversal Utilities
- Column Elements and Expressions¶
- Schema Definition Language
- SQL Datatype Objects
- Engine and Connection Use
- Core API Basics
Project Versions
- Previous: SQL Statements and Expressions API
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- On this page:
- Column Elements and Expressions
- Column Element Foundational Constructors
- Column Element Modifier Constructors
- Column Element Class Documentation
BinaryExpression
BindParameter
Case
Cast
ClauseList
ColumnClause
ColumnCollection
ColumnCollection.add()
ColumnCollection.as_readonly()
ColumnCollection.clear()
ColumnCollection.compare()
ColumnCollection.contains_column()
ColumnCollection.corresponding_column()
ColumnCollection.get()
ColumnCollection.items()
ColumnCollection.keys()
ColumnCollection.update()
ColumnCollection.values()
ColumnElement
ColumnElement.__eq__()
ColumnElement.__le__()
ColumnElement.__lt__()
ColumnElement.__ne__()
ColumnElement.all_()
ColumnElement.allows_lambda
ColumnElement.anon_key_label
ColumnElement.anon_label
ColumnElement.any_()
ColumnElement.asc()
ColumnElement.base_columns
ColumnElement.between()
ColumnElement.bitwise_and()
ColumnElement.bitwise_lshift()
ColumnElement.bitwise_not()
ColumnElement.bitwise_or()
ColumnElement.bitwise_rshift()
ColumnElement.bitwise_xor()
ColumnElement.bool_op()
ColumnElement.cast()
ColumnElement.collate()
ColumnElement.comparator
ColumnElement.compare()
ColumnElement.compile()
ColumnElement.concat()
ColumnElement.contains()
ColumnElement.desc()
ColumnElement.description
ColumnElement.distinct()
ColumnElement.endswith()
ColumnElement.entity_namespace
ColumnElement.expression
ColumnElement.foreign_keys
ColumnElement.get_children()
ColumnElement.icontains()
ColumnElement.iendswith()
ColumnElement.ilike()
ColumnElement.in_()
ColumnElement.inherit_cache
ColumnElement.is_()
ColumnElement.is_clause_element
ColumnElement.is_distinct_from()
ColumnElement.is_dml
ColumnElement.is_not()
ColumnElement.is_not_distinct_from()
ColumnElement.is_selectable
ColumnElement.isnot()
ColumnElement.isnot_distinct_from()
ColumnElement.istartswith()
ColumnElement.key
ColumnElement.label()
ColumnElement.like()
ColumnElement.match()
ColumnElement.negation_clause
ColumnElement.not_ilike()
ColumnElement.not_in()
ColumnElement.not_like()
ColumnElement.notilike()
ColumnElement.notin_()
ColumnElement.notlike()
ColumnElement.nulls_first()
ColumnElement.nulls_last()
ColumnElement.nullsfirst()
ColumnElement.nullslast()
ColumnElement.op()
ColumnElement.operate()
ColumnElement.params()
ColumnElement.primary_key
ColumnElement.proxy_set
ColumnElement.regexp_match()
ColumnElement.regexp_replace()
ColumnElement.reverse_operate()
ColumnElement.self_group()
ColumnElement.shares_lineage()
ColumnElement.startswith()
ColumnElement.stringify_dialect
ColumnElement.supports_execution
ColumnElement.timetuple
ColumnElement.type
ColumnElement.unique_params()
ColumnElement.uses_inspection
ColumnExpressionArgument
ColumnOperators
ColumnOperators.__add__()
ColumnOperators.__and__()
ColumnOperators.__eq__()
ColumnOperators.__floordiv__()
ColumnOperators.__ge__()
ColumnOperators.__getitem__()
ColumnOperators.__gt__()
ColumnOperators.__hash__()
ColumnOperators.__invert__()
ColumnOperators.__le__()
ColumnOperators.__lshift__()
ColumnOperators.__lt__()
ColumnOperators.__mod__()
ColumnOperators.__mul__()
ColumnOperators.__ne__()
ColumnOperators.__neg__()
ColumnOperators.__or__()
ColumnOperators.__radd__()
ColumnOperators.__rfloordiv__()
ColumnOperators.__rmod__()
ColumnOperators.__rmul__()
ColumnOperators.__rshift__()
ColumnOperators.__rsub__()
ColumnOperators.__rtruediv__()
ColumnOperators.__sa_operate__()
ColumnOperators.__sub__()
ColumnOperators.__truediv__()
ColumnOperators.all_()
ColumnOperators.any_()
ColumnOperators.asc()
ColumnOperators.between()
ColumnOperators.bitwise_and()
ColumnOperators.bitwise_lshift()
ColumnOperators.bitwise_not()
ColumnOperators.bitwise_or()
ColumnOperators.bitwise_rshift()
ColumnOperators.bitwise_xor()
ColumnOperators.bool_op()
ColumnOperators.collate()
ColumnOperators.concat()
ColumnOperators.contains()
ColumnOperators.desc()
ColumnOperators.distinct()
ColumnOperators.endswith()
ColumnOperators.icontains()
ColumnOperators.iendswith()
ColumnOperators.ilike()
ColumnOperators.in_()
ColumnOperators.is_()
ColumnOperators.is_distinct_from()
ColumnOperators.is_not()
ColumnOperators.is_not_distinct_from()
ColumnOperators.isnot()
ColumnOperators.isnot_distinct_from()
ColumnOperators.istartswith()
ColumnOperators.like()
ColumnOperators.match()
ColumnOperators.not_ilike()
ColumnOperators.not_in()
ColumnOperators.not_like()
ColumnOperators.notilike()
ColumnOperators.notin_()
ColumnOperators.notlike()
ColumnOperators.nulls_first()
ColumnOperators.nulls_last()
ColumnOperators.nullsfirst()
ColumnOperators.nullslast()
ColumnOperators.op()
ColumnOperators.operate()
ColumnOperators.regexp_match()
ColumnOperators.regexp_replace()
ColumnOperators.reverse_operate()
ColumnOperators.startswith()
ColumnOperators.timetuple
Extract
False_
FunctionFilter
Label
Null
Operators
Over
SQLColumnExpression
TextClause
TryCast
Tuple
WithinGroup
WrapsColumnExpression
True_
TypeCoerce
UnaryExpression
- Column Element Typing Utilities
Column Elements and Expressions¶
The expression API consists of a series of classes each of which represents a
specific lexical element within a SQL string. Composed together
into a larger structure, they form a statement construct that may
be compiled into a string representation that can be passed to a database.
The classes are organized into a hierarchy that begins at the basemost
ClauseElement
class. Key subclasses include ColumnElement
,
which represents the role of any column-based expression
in a SQL statement, such as in the columns clause, WHERE clause, and ORDER BY
clause, and FromClause
, which represents the role of a token that
is placed in the FROM clause of a SELECT statement.
Column Element Foundational Constructors¶
Standalone functions imported from the sqlalchemy
namespace which are
used when building up SQLAlchemy Expression Language constructs.
Object Name | Description |
---|---|
and_(*clauses) |
Produce a conjunction of expressions joined by |
bindparam(key[, value, type_, unique, ...]) |
Produce a “bound expression”. |
bitwise_not(expr) |
Produce a unary bitwise NOT clause, typically via the |
case(*whens, [value, else_]) |
Produce a |
cast(expression, type_) |
Produce a |
column(text[, type_, is_literal, _selectable]) |
Produce a |
Represent a ‘custom’ operator. |
|
distinct(expr) |
Produce an column-expression-level unary |
extract(field, expr) |
Return a |
false() |
Return a |
Generate SQL function expressions. |
|
lambda_stmt(lmb[, enable_tracking, track_closure_variables, track_on, ...]) |
Produce a SQL statement that is cached as a lambda. |
literal(value[, type_, literal_execute]) |
Return a literal clause, bound to a bind parameter. |
literal_column(text[, type_]) |
Produce a |
not_(clause) |
Return a negation of the given clause, i.e. |
null() |
Return a constant |
or_(*clauses) |
Produce a conjunction of expressions joined by |
outparam(key[, type_]) |
Create an ‘OUT’ parameter for usage in functions (stored procedures), for databases which support them. |
Represent a SQL identifier combined with quoting preferences. |
|
text(text) |
Construct a new |
true() |
Return a constant |
try_cast(expression, type_) |
Produce a |
tuple_(*clauses, [types]) |
Return a |
type_coerce(expression, type_) |
Associate a SQL expression with a particular type, without rendering
|
- function sqlalchemy.sql.expression.and_(*clauses)¶
Produce a conjunction of expressions joined by
AND
.E.g.:
from sqlalchemy import and_ stmt = select(users_table).where( and_( users_table.c.name == 'wendy', users_table.c.enrolled == True ) )
The
and_()
conjunction is also available using the Python&
operator (though note that compound expressions need to be parenthesized in order to function with Python operator precedence behavior):stmt = select(users_table).where( (users_table.c.name == 'wendy') & (users_table.c.enrolled == True) )
The
and_()
operation is also implicit in some cases; theSelect.where()
method for example can be invoked multiple times against a statement, which will have the effect of each clause being combined usingand_()
:stmt = select(users_table).\ where(users_table.c.name == 'wendy').\ where(users_table.c.enrolled == True)
The
and_()
construct must be given at least one positional argument in order to be valid; aand_()
construct with no arguments is ambiguous. To produce an “empty” or dynamically generatedand_()
expression, from a given list of expressions, a “default” element oftrue()
(or justTrue
) should be specified:from sqlalchemy import true criteria = and_(true(), *expressions)
The above expression will compile to SQL as the expression
true
or1 = 1
, depending on backend, if no other expressions are present. If expressions are present, then thetrue()
value is ignored as it does not affect the outcome of an AND expression that has other elements.Deprecated since version 1.4: The
and_()
element now requires that at least one argument is passed; creating theand_()
construct with no arguments is deprecated, and will emit a deprecation warning while continuing to produce a blank SQL string.See also
- function sqlalchemy.sql.expression.bindparam(key: str | None, value: Any = _NoArg.NO_ARG, type_: _TypeEngineArgument[_T] | None = None, unique: bool = False, required: bool | Literal[_NoArg.NO_ARG] = _NoArg.NO_ARG, quote: bool | None = None, callable_: Callable[[], Any] | None = None, expanding: bool = False, isoutparam: bool = False, literal_execute: bool = False) → BindParameter[_T]¶
Produce a “bound expression”.
The return value is an instance of
BindParameter
; this is aColumnElement
subclass which represents a so-called “placeholder” value in a SQL expression, the value of which is supplied at the point at which the statement in executed against a database connection.In SQLAlchemy, the
bindparam()
construct has the ability to carry along the actual value that will be ultimately used at expression time. In this way, it serves not just as a “placeholder” for eventual population, but also as a means of representing so-called “unsafe” values which should not be rendered directly in a SQL statement, but rather should be passed along to the DBAPI as values which need to be correctly escaped and potentially handled for type-safety.When using
bindparam()
explicitly, the use case is typically one of traditional deferment of parameters; thebindparam()
construct accepts a name which can then be referred to at execution time:from sqlalchemy import bindparam stmt = select(users_table).where( users_table.c.name == bindparam("username") )
The above statement, when rendered, will produce SQL similar to:
SELECT id, name FROM user WHERE name = :username
In order to populate the value of
:username
above, the value would typically be applied at execution time to a method likeConnection.execute()
:result = connection.execute(stmt, {"username": "wendy"})
Explicit use of
bindparam()
is also common when producing UPDATE or DELETE statements that are to be invoked multiple times, where the WHERE criterion of the statement is to change on each invocation, such as:stmt = ( users_table.update() .where(user_table.c.name == bindparam("username")) .values(fullname=bindparam("fullname")) ) connection.execute( stmt, [ {"username": "wendy", "fullname": "Wendy Smith"}, {"username": "jack", "fullname": "Jack Jones"}, ], )
SQLAlchemy’s Core expression system makes wide use of
bindparam()
in an implicit sense. It is typical that Python literal values passed to virtually all SQL expression functions are coerced into fixedbindparam()
constructs. For example, given a comparison operation such as:expr = users_table.c.name == 'Wendy'
The above expression will produce a
BinaryExpression
construct, where the left side is theColumn
object representing thename
column, and the right side is aBindParameter
representing the literal value:print(repr(expr.right)) BindParameter('%(4327771088 name)s', 'Wendy', type_=String())
The expression above will render SQL such as:
user.name = :name_1
Where the
:name_1
parameter name is an anonymous name. The actual stringWendy
is not in the rendered string, but is carried along where it is later used within statement execution. If we invoke a statement like the following:stmt = select(users_table).where(users_table.c.name == 'Wendy') result = connection.execute(stmt)
We would see SQL logging output as:
SELECT "user".id, "user".name FROM "user" WHERE "user".name = %(name_1)s {'name_1': 'Wendy'}
Above, we see that
Wendy
is passed as a parameter to the database, while the placeholder:name_1
is rendered in the appropriate form for the target database, in this case the PostgreSQL database.Similarly,
bindparam()
is invoked automatically when working with CRUD statements as far as the “VALUES” portion is concerned. Theinsert()
construct produces anINSERT
expression which will, at statement execution time, generate bound placeholders based on the arguments passed, as in:stmt = users_table.insert() result = connection.execute(stmt, {"name": "Wendy"})
The above will produce SQL output as:
INSERT INTO "user" (name) VALUES (%(name)s) {'name': 'Wendy'}
The
Insert
construct, at compilation/execution time, rendered a singlebindparam()
mirroring the column namename
as a result of the singlename
parameter we passed to theConnection.execute()
method.- Parameters:
key¶ –
the key (e.g. the name) for this bind param. Will be used in the generated SQL statement for dialects that use named parameters. This value may be modified when part of a compilation operation, if other
BindParameter
objects exist with the same key, or if its length is too long and truncation is required.If omitted, an “anonymous” name is generated for the bound parameter; when given a value to bind, the end result is equivalent to calling upon the
literal()
function with a value to bind, particularly if thebindparam.unique
parameter is also provided.value¶ – Initial value for this bind param. Will be used at statement execution time as the value for this parameter passed to the DBAPI, if no other value is indicated to the statement execution method for this particular parameter name. Defaults to
None
.callable_¶ – A callable function that takes the place of “value”. The function will be called at statement execution time to determine the ultimate value. Used for scenarios where the actual bind value cannot be determined at the point at which the clause construct is created, but embedded bind values are still desirable.
type_¶ –
A
TypeEngine
class or instance representing an optional datatype for thisbindparam()
. If not passed, a type may be determined automatically for the bind, based on the given value; for example, trivial Python types such asstr
,int
,bool
may result in theString
,Integer
orBoolean
types being automatically selected.The type of a
bindparam()
is significant especially in that the type will apply pre-processing to the value before it is passed to the database. For example, abindparam()
which refers to a datetime value, and is specified as holding theDateTime
type, may apply conversion needed to the value (such as stringification on SQLite) before passing the value to the database.unique¶ – if True, the key name of this
BindParameter
will be modified if anotherBindParameter
of the same name already has been located within the containing expression. This flag is used generally by the internals when producing so-called “anonymous” bound expressions, it isn’t generally applicable to explicitly-namedbindparam()
constructs.required¶ – If
True
, a value is required at execution time. If not passed, it defaults toTrue
if neitherbindparam.value
orbindparam.callable
were passed. If either of these parameters are present, thenbindparam.required
defaults toFalse
.quote¶ – True if this parameter name requires quoting and is not currently known as a SQLAlchemy reserved word; this currently only applies to the Oracle backend, where bound names must sometimes be quoted.
isoutparam¶ – if True, the parameter should be treated like a stored procedure “OUT” parameter. This applies to backends such as Oracle which support OUT parameters.
expanding¶ –
if True, this parameter will be treated as an “expanding” parameter at execution time; the parameter value is expected to be a sequence, rather than a scalar value, and the string SQL statement will be transformed on a per-execution basis to accommodate the sequence with a variable number of parameter slots passed to the DBAPI. This is to allow statement caching to be used in conjunction with an IN clause.
Note
The “expanding” feature does not support “executemany”- style parameter sets.
New in version 1.2.
Changed in version 1.3: the “expanding” bound parameter feature now supports empty lists.
literal_execute¶ –
if True, the bound parameter will be rendered in the compile phase with a special “POSTCOMPILE” token, and the SQLAlchemy compiler will render the final value of the parameter into the SQL statement at statement execution time, omitting the value from the parameter dictionary / list passed to DBAPI
cursor.execute()
. This produces a similar effect as that of using theliteral_binds
, compilation flag, however takes place as the statement is sent to the DBAPIcursor.execute()
method, rather than when the statement is compiled. The primary use of this capability is for rendering LIMIT / OFFSET clauses for database drivers that can’t accommodate for bound parameters in these contexts, while allowing SQL constructs to be cacheable at the compilation level.New in version 1.4: Added “post compile” bound parameters
See also
- function sqlalchemy.sql.expression.bitwise_not(expr: _ColumnExpressionArgument[_T]) → UnaryExpression[_T]¶
Produce a unary bitwise NOT clause, typically via the
~
operator.Not to be confused with boolean negation
not_()
.New in version 2.0.2.
See also
- function sqlalchemy.sql.expression.case(*whens: typing_Tuple[_ColumnExpressionArgument[bool], Any] | Mapping[Any, Any], value: Any | None = None, else_: Any | None = None) → Case[Any]¶
Produce a
CASE
expression.The
CASE
construct in SQL is a conditional object that acts somewhat analogously to an “if/then” construct in other languages. It returns an instance ofCase
.case()
in its usual form is passed a series of “when” constructs, that is, a list of conditions and results as tuples:from sqlalchemy import case stmt = select(users_table).\ where( case( (users_table.c.name == 'wendy', 'W'), (users_table.c.name == 'jack', 'J'), else_='E' ) )
The above statement will produce SQL resembling:
SELECT id, name FROM user WHERE CASE WHEN (name = :name_1) THEN :param_1 WHEN (name = :name_2) THEN :param_2 ELSE :param_3 END
When simple equality expressions of several values against a single parent column are needed,
case()
also has a “shorthand” format used via thecase.value
parameter, which is passed a column expression to be compared. In this form, thecase.whens
parameter is passed as a dictionary containing expressions to be compared against keyed to result expressions. The statement below is equivalent to the preceding statement:stmt = select(users_table).\ where( case( {"wendy": "W", "jack": "J"}, value=users_table.c.name, else_='E' ) )
The values which are accepted as result values in
case.whens
as well as withcase.else_
are coerced from Python literals intobindparam()
constructs. SQL expressions, e.g.ColumnElement
constructs, are accepted as well. To coerce a literal string expression into a constant expression rendered inline, use theliteral_column()
construct, as in:from sqlalchemy import case, literal_column case( ( orderline.c.qty > 100, literal_column("'greaterthan100'") ), ( orderline.c.qty > 10, literal_column("'greaterthan10'") ), else_=literal_column("'lessthan10'") )
The above will render the given constants without using bound parameters for the result values (but still for the comparison values), as in:
CASE WHEN (orderline.qty > :qty_1) THEN 'greaterthan100' WHEN (orderline.qty > :qty_2) THEN 'greaterthan10' ELSE 'lessthan10' END
- Parameters:
*whens¶ –
The criteria to be compared against,
case.whens
accepts two different forms, based on whether or notcase.value
is used.Changed in version 1.4: the
case()
function now accepts the series of WHEN conditions positionallyIn the first form, it accepts multiple 2-tuples passed as positional arguments; each 2-tuple consists of
(<sql expression>, <value>)
, where the SQL expression is a boolean expression and “value” is a resulting value, e.g.:case( (users_table.c.name == 'wendy', 'W'), (users_table.c.name == 'jack', 'J') )
In the second form, it accepts a Python dictionary of comparison values mapped to a resulting value; this form requires
case.value
to be present, and values will be compared using the==
operator, e.g.:case( {"wendy": "W", "jack": "J"}, value=users_table.c.name )
value¶ – An optional SQL expression which will be used as a fixed “comparison point” for candidate values within a dictionary passed to
case.whens
.else_¶ – An optional SQL expression which will be the evaluated result of the
CASE
construct if all expressions withincase.whens
evaluate to false. When omitted, most databases will produce a result of NULL if none of the “when” expressions evaluate to true.
- function sqlalchemy.sql.expression.cast(expression: _ColumnExpressionOrLiteralArgument[Any], type_: _TypeEngineArgument[_T]) → Cast[_T]¶
Produce a
CAST
expression.cast()
returns an instance ofCast
.E.g.:
from sqlalchemy import cast, Numeric stmt = select(cast(product_table.c.unit_price, Numeric(10, 4)))
The above statement will produce SQL resembling:
SELECT CAST(unit_price AS NUMERIC(10, 4)) FROM product
The
cast()
function performs two distinct functions when used. The first is that it renders theCAST
expression within the resulting SQL string. The second is that it associates the given type (e.g.TypeEngine
class or instance) with the column expression on the Python side, which means the expression will take on the expression operator behavior associated with that type, as well as the bound-value handling and result-row-handling behavior of the type.An alternative to
cast()
is thetype_coerce()
function. This function performs the second task of associating an expression with a specific type, but does not render theCAST
expression in SQL.- Parameters:
expression¶ – A SQL expression, such as a
ColumnElement
expression or a Python string which will be coerced into a bound literal value.type_¶ – A
TypeEngine
class or instance indicating the type to which theCAST
should apply.
See also
try_cast()
- an alternative to CAST that results in NULLs when the cast fails, instead of raising an error. Only supported by some dialects.type_coerce()
- an alternative to CAST that coerces the type on the Python side only, which is often sufficient to generate the correct SQL and data coercion.
- function sqlalchemy.sql.expression.column(text: str, type_: _TypeEngineArgument[_T] | None = None, is_literal: bool = False, _selectable: FromClause | None = None) → ColumnClause[_T]¶
Produce a
ColumnClause
object.The
ColumnClause
is a lightweight analogue to theColumn
class. Thecolumn()
function can be invoked with just a name alone, as in:from sqlalchemy import column id, name = column("id"), column("name") stmt = select(id, name).select_from("user")
The above statement would produce SQL like:
SELECT id, name FROM user
Once constructed,
column()
may be used like any other SQL expression element such as withinselect()
constructs:from sqlalchemy.sql import column id, name = column("id"), column("name") stmt = select(id, name).select_from("user")
The text handled by
column()
is assumed to be handled like the name of a database column; if the string contains mixed case, special characters, or matches a known reserved word on the target backend, the column expression will render using the quoting behavior determined by the backend. To produce a textual SQL expression that is rendered exactly without any quoting, useliteral_column()
instead, or passTrue
as the value ofcolumn.is_literal
. Additionally, full SQL statements are best handled using thetext()
construct.column()
can be used in a table-like fashion by combining it with thetable()
function (which is the lightweight analogue toTable
) to produce a working table construct with minimal boilerplate:from sqlalchemy import table, column, select user = table("user", column("id"), column("name"), column("description"), ) stmt = select(user.c.description).where(user.c.name == 'wendy')
A
column()
/table()
construct like that illustrated above can be created in an ad-hoc fashion and is not associated with anyMetaData
, DDL, or events, unlike itsTable
counterpart.- Parameters:
text¶ – the text of the element.
type¶ –
TypeEngine
object which can associate thisColumnClause
with a type.is_literal¶ – if True, the
ColumnClause
is assumed to be an exact expression that will be delivered to the output with no quoting rules applied regardless of case sensitive settings. theliteral_column()
function essentially invokescolumn()
while passingis_literal=True
.
- class sqlalchemy.sql.expression.custom_op¶
Represent a ‘custom’ operator.
custom_op
is normally instantiated when theOperators.op()
orOperators.bool_op()
methods are used to create a custom operator callable. The class can also be used directly when programmatically constructing expressions. E.g. to represent the “factorial” operation:from sqlalchemy.sql import UnaryExpression from sqlalchemy.sql import operators from sqlalchemy import Numeric unary = UnaryExpression(table.c.somecolumn, modifier=operators.custom_op("!"), type_=Numeric)
Class signature
class
sqlalchemy.sql.expression.custom_op
(sqlalchemy.sql.expression.OperatorType
,typing.Generic
)
- function sqlalchemy.sql.expression.distinct(expr: _ColumnExpressionArgument[_T]) → UnaryExpression[_T]¶
Produce an column-expression-level unary
DISTINCT
clause.This applies the
DISTINCT
keyword to an individual column expression (e.g. not the whole statement), and renders specifically in that column position; this is used for containment within an aggregate function, as in:from sqlalchemy import distinct, func stmt = select(users_table.c.id, func.count(distinct(users_table.c.name)))
The above would produce an statement resembling:
SELECT user.id, count(DISTINCT user.name) FROM user
Tip
The
distinct()
function does not apply DISTINCT to the full SELECT statement, instead applying a DISTINCT modifier to individual column expressions. For generalSELECT DISTINCT
support, use theSelect.distinct()
method onSelect
.The
distinct()
function is also available as a column-level method, e.g.ColumnElement.distinct()
, as in:stmt = select(func.count(users_table.c.name.distinct()))
The
distinct()
operator is different from theSelect.distinct()
method ofSelect
, which produces aSELECT
statement withDISTINCT
applied to the result set as a whole, e.g. aSELECT DISTINCT
expression. See that method for further information.
- function sqlalchemy.sql.expression.extract(field: str, expr: _ColumnExpressionArgument[Any]) → Extract¶
Return a
Extract
construct.This is typically available as
extract()
as well asfunc.extract
from thefunc
namespace.- Parameters:
E.g.:
from sqlalchemy import extract from sqlalchemy import table, column logged_table = table("user", column("id"), column("date_created"), ) stmt = select(logged_table.c.id).where( extract("YEAR", logged_table.c.date_created) == 2021 )
In the above example, the statement is used to select ids from the database where the
YEAR
component matches a specific value.Similarly, one can also select an extracted component:
stmt = select( extract("YEAR", logged_table.c.date_created) ).where(logged_table.c.id == 1)
The implementation of
EXTRACT
may vary across database backends. Users are reminded to consult their database documentation.
- function sqlalchemy.sql.expression.false() → False_¶
Return a
False_
construct.E.g.:
>>> from sqlalchemy import false >>> print(select(t.c.x).where(false()))
SELECT x FROM t WHERE falseA backend which does not support true/false constants will render as an expression against 1 or 0:
>>> print(select(t.c.x).where(false()))
SELECT x FROM t WHERE 0 = 1The
true()
andfalse()
constants also feature “short circuit” operation within anand_()
oror_()
conjunction:>>> print(select(t.c.x).where(or_(t.c.x > 5, true())))
SELECT x FROM t WHERE true>>> print(select(t.c.x).where(and_(t.c.x > 5, false())))SELECT x FROM t WHERE falseSee also
- sqlalchemy.sql.expression.func = <sqlalchemy.sql.functions._FunctionGenerator object>¶
Generate SQL function expressions.
func
is a special object instance which generates SQL functions based on name-based attributes, e.g.:>>> print(func.count(1))
count(:param_1)The returned object is an instance of
Function
, and is a column-oriented SQL element like any other, and is used in that way:>>> print(select(func.count(table.c.id)))
SELECT count(sometable.id) FROM sometableAny name can be given to
func
. If the function name is unknown to SQLAlchemy, it will be rendered exactly as is. For common SQL functions which SQLAlchemy is aware of, the name may be interpreted as a generic function which will be compiled appropriately to the target database:>>> print(func.current_timestamp())
CURRENT_TIMESTAMPTo call functions which are present in dot-separated packages, specify them in the same manner:
>>> print(func.stats.yield_curve(5, 10))
stats.yield_curve(:yield_curve_1, :yield_curve_2)SQLAlchemy can be made aware of the return type of functions to enable type-specific lexical and result-based behavior. For example, to ensure that a string-based function returns a Unicode value and is similarly treated as a string in expressions, specify
Unicode
as the type:>>> print(func.my_string(u'hi', type_=Unicode) + ' ' + ... func.my_string(u'there', type_=Unicode))
my_string(:my_string_1) || :my_string_2 || my_string(:my_string_3)The object returned by a
func
call is usually an instance ofFunction
. This object meets the “column” interface, including comparison and labeling functions. The object can also be passed theConnectable.execute()
method of aConnection
orEngine
, where it will be wrapped inside of a SELECT statement first:print(connection.execute(func.current_timestamp()).scalar())
In a few exception cases, the
func
accessor will redirect a name to a built-in expression such ascast()
orextract()
, as these names have well-known meaning but are not exactly the same as “functions” from a SQLAlchemy perspective.Functions which are interpreted as “generic” functions know how to calculate their return type automatically. For a listing of known generic functions, see SQL and Generic Functions.
Note
The
func
construct has only limited support for calling standalone “stored procedures”, especially those with special parameterization concerns.See the section Calling Stored Procedures and User Defined Functions for details on how to use the DBAPI-level
callproc()
method for fully traditional stored procedures.
- function sqlalchemy.sql.expression.lambda_stmt(lmb: Callable[[], Any], enable_tracking: bool = True, track_closure_variables: bool = True, track_on: object | None = None, global_track_bound_values: bool = True, track_bound_values: bool = True, lambda_cache: MutableMapping[Tuple[Any, ...], NonAnalyzedFunction | AnalyzedFunction] | None = None) → StatementLambdaElement¶
Produce a SQL statement that is cached as a lambda.
The Python code object within the lambda is scanned for both Python literals that will become bound parameters as well as closure variables that refer to Core or ORM constructs that may vary. The lambda itself will be invoked only once per particular set of constructs detected.
E.g.:
from sqlalchemy import lambda_stmt stmt = lambda_stmt(lambda: table.select()) stmt += lambda s: s.where(table.c.id == 5) result = connection.execute(stmt)
The object returned is an instance of
StatementLambdaElement
.New in version 1.4.
- Parameters:
lmb¶ – a Python function, typically a lambda, which takes no arguments and returns a SQL expression construct
enable_tracking¶ – when False, all scanning of the given lambda for changes in closure variables or bound parameters is disabled. Use for a lambda that produces the identical results in all cases with no parameterization.
track_closure_variables¶ – when False, changes in closure variables within the lambda will not be scanned. Use for a lambda where the state of its closure variables will never change the SQL structure returned by the lambda.
track_bound_values¶ – when False, bound parameter tracking will be disabled for the given lambda. Use for a lambda that either does not produce any bound values, or where the initial bound values never change.
global_track_bound_values¶ – when False, bound parameter tracking will be disabled for the entire statement including additional links added via the
StatementLambdaElement.add_criteria()
method.lambda_cache¶ – a dictionary or other mapping-like object where information about the lambda’s Python code as well as the tracked closure variables in the lambda itself will be stored. Defaults to a global LRU cache. This cache is independent of the “compiled_cache” used by the
Connection
object.
- function sqlalchemy.sql.expression.literal(value: Any, type_: _TypeEngineArgument[Any] | None = None, literal_execute: bool = False) → BindParameter[Any]¶
Return a literal clause, bound to a bind parameter.
Literal clauses are created automatically when non-
ClauseElement
objects (such as strings, ints, dates, etc.) are used in a comparison operation with aColumnElement
subclass, such as aColumn
object. Use this function to force the generation of a literal clause, which will be created as aBindParameter
with a bound value.- Parameters:
value¶ – the value to be bound. Can be any Python object supported by the underlying DB-API, or is translatable via the given type argument.
type_¶ – an optional
TypeEngine
which will provide bind-parameter translation for this literal.literal_execute¶ –
optional bool, when True, the SQL engine will attempt to render the bound value directly in the SQL statement at execution time rather than providing as a parameter value.
New in version 2.0.
- function sqlalchemy.sql.expression.literal_column(text: str, type_: _TypeEngineArgument[_T] | None = None) → ColumnClause[_T]¶
Produce a
ColumnClause
object that has thecolumn.is_literal
flag set to True.literal_column()
is similar tocolumn()
, except that it is more often used as a “standalone” column expression that renders exactly as stated; whilecolumn()
stores a string name that will be assumed to be part of a table and may be quoted as such,literal_column()
can be that, or any other arbitrary column-oriented expression.- Parameters:
text¶ – the text of the expression; can be any SQL expression. Quoting rules will not be applied. To specify a column-name expression which should be subject to quoting rules, use the
column()
function.type_¶ – an optional
TypeEngine
object which will provide result-set translation and additional expression semantics for this column. If left asNone
the type will beNullType
.
- function sqlalchemy.sql.expression.not_(clause: _ColumnExpressionArgument[_T]) → ColumnElement[_T]¶
Return a negation of the given clause, i.e.
NOT(clause)
.The
~
operator is also overloaded on allColumnElement
subclasses to produce the same result.
- function sqlalchemy.sql.expression.or_(*clauses)¶
Produce a conjunction of expressions joined by
OR
.E.g.:
from sqlalchemy import or_ stmt = select(users_table).where( or_( users_table.c.name == 'wendy', users_table.c.name == 'jack' ) )
The
or_()
conjunction is also available using the Python|
operator (though note that compound expressions need to be parenthesized in order to function with Python operator precedence behavior):stmt = select(users_table).where( (users_table.c.name == 'wendy') | (users_table.c.name == 'jack') )
The
or_()
construct must be given at least one positional argument in order to be valid; aor_()
construct with no arguments is ambiguous. To produce an “empty” or dynamically generatedor_()
expression, from a given list of expressions, a “default” element offalse()
(or justFalse
) should be specified:from sqlalchemy import false or_criteria = or_(false(), *expressions)
The above expression will compile to SQL as the expression
false
or0 = 1
, depending on backend, if no other expressions are present. If expressions are present, then thefalse()
value is ignored as it does not affect the outcome of an OR expression which has other elements.Deprecated since version 1.4: The
or_()
element now requires that at least one argument is passed; creating theor_()
construct with no arguments is deprecated, and will emit a deprecation warning while continuing to produce a blank SQL string.See also
- function sqlalchemy.sql.expression.outparam(key: str, type_: TypeEngine[_T] | None = None) → BindParameter[_T]¶
Create an ‘OUT’ parameter for usage in functions (stored procedures), for databases which support them.
The
outparam
can be used like a regular function parameter. The “output” value will be available from theCursorResult
object via itsout_parameters
attribute, which returns a dictionary containing the values.
- function sqlalchemy.sql.expression.text(text: str) → TextClause¶
Construct a new
TextClause
clause, representing a textual SQL string directly.E.g.:
from sqlalchemy import text t = text("SELECT * FROM users") result = connection.execute(t)
The advantages
text()
provides over a plain string are backend-neutral support for bind parameters, per-statement execution options, as well as bind parameter and result-column typing behavior, allowing SQLAlchemy type constructs to play a role when executing a statement that is specified literally. The construct can also be provided with a.c
collection of column elements, allowing it to be embedded in other SQL expression constructs as a subquery.Bind parameters are specified by name, using the format
:name
. E.g.:t = text("SELECT * FROM users WHERE id=:user_id") result = connection.execute(t, {"user_id": 12})
For SQL statements where a colon is required verbatim, as within an inline string, use a backslash to escape:
t = text(r"SELECT * FROM users WHERE name='\:username'")
The
TextClause
construct includes methods which can provide information about the bound parameters as well as the column values which would be returned from the textual statement, assuming it’s an executable SELECT type of statement. TheTextClause.bindparams()
method is used to provide bound parameter detail, andTextClause.columns()
method allows specification of return columns including names and types:t = text("SELECT * FROM users WHERE id=:user_id").\ bindparams(user_id=7).\ columns(id=Integer, name=String) for id, name in connection.execute(t): print(id, name)
The
text()
construct is used in cases when a literal string SQL fragment is specified as part of a larger query, such as for the WHERE clause of a SELECT statement:s = select(users.c.id, users.c.name).where(text("id=:user_id")) result = connection.execute(s, {"user_id": 12})
text()
is also used for the construction of a full, standalone statement using plain text. As such, SQLAlchemy refers to it as anExecutable
object and may be used like any other statement passed to an.execute()
method.- Parameters:
text¶ –
the text of the SQL statement to be created. Use
:<param>
to specify bind parameters; they will be compiled to their engine-specific format.
- function sqlalchemy.sql.expression.true() → True_¶
Return a constant
True_
construct.E.g.:
>>> from sqlalchemy import true >>> print(select(t.c.x).where(true()))
SELECT x FROM t WHERE trueA backend which does not support true/false constants will render as an expression against 1 or 0:
>>> print(select(t.c.x).where(true()))
SELECT x FROM t WHERE 1 = 1The
true()
andfalse()
constants also feature “short circuit” operation within anand_()
oror_()
conjunction:>>> print(select(t.c.x).where(or_(t.c.x > 5, true())))
SELECT x FROM t WHERE true>>> print(select(t.c.x).where(and_(t.c.x > 5, false())))SELECT x FROM t WHERE falseSee also
- function sqlalchemy.sql.expression.try_cast(expression: _ColumnExpressionOrLiteralArgument[Any], type_: _TypeEngineArgument[_T]) → TryCast[_T]¶
Produce a
TRY_CAST
expression for backends which support it; this is aCAST
which returns NULL for un-castable conversions.In SQLAlchemy, this construct is supported only by the SQL Server dialect, and will raise a
CompileError
if used on other included backends. However, third party backends may also support this construct.Tip
As
try_cast()
originates from the SQL Server dialect, it’s importable both fromsqlalchemy.
as well as fromsqlalchemy.dialects.mssql
.try_cast()
returns an instance ofTryCast
and generally behaves similarly to theCast
construct; at the SQL level, the difference betweenCAST
andTRY_CAST
is thatTRY_CAST
returns NULL for an un-castable expression, such as attempting to cast a string"hi"
to an integer value.E.g.:
from sqlalchemy import select, try_cast, Numeric stmt = select( try_cast(product_table.c.unit_price, Numeric(10, 4)) )
The above would render on Microsoft SQL Server as:
SELECT TRY_CAST (product_table.unit_price AS NUMERIC(10, 4)) FROM product_table
New in version 2.0.14:
try_cast()
has been generalized from the SQL Server dialect into a general use construct that may be supported by additional dialects.
- function sqlalchemy.sql.expression.tuple_(*clauses: _ColumnExpressionArgument[Any], types: Sequence[_TypeEngineArgument[Any]] | None = None) → Tuple¶
Return a
Tuple
.Main usage is to produce a composite IN construct using
ColumnOperators.in_()
from sqlalchemy import tuple_ tuple_(table.c.col1, table.c.col2).in_( [(1, 2), (5, 12), (10, 19)] )
Changed in version 1.3.6: Added support for SQLite IN tuples.
Warning
The composite IN construct is not supported by all backends, and is currently known to work on PostgreSQL, MySQL, and SQLite. Unsupported backends will raise a subclass of
DBAPIError
when such an expression is invoked.
- function sqlalchemy.sql.expression.type_coerce(expression: _ColumnExpressionOrLiteralArgument[Any], type_: _TypeEngineArgument[_T]) → TypeCoerce[_T]¶
Associate a SQL expression with a particular type, without rendering
CAST
.E.g.:
from sqlalchemy import type_coerce stmt = select(type_coerce(log_table.date_string, StringDateTime()))
The above construct will produce a
TypeCoerce
object, which does not modify the rendering in any way on the SQL side, with the possible exception of a generated label if used in a columns clause context:SELECT date_string AS date_string FROM log
When result rows are fetched, the
StringDateTime
type processor will be applied to result rows on behalf of thedate_string
column.Note
the
type_coerce()
construct does not render any SQL syntax of its own, including that it does not imply parenthesization. Please useTypeCoerce.self_group()
if explicit parenthesization is required.In order to provide a named label for the expression, use
ColumnElement.label()
:stmt = select( type_coerce(log_table.date_string, StringDateTime()).label('date') )
A type that features bound-value handling will also have that behavior take effect when literal values or
bindparam()
constructs are passed totype_coerce()
as targets. For example, if a type implements theTypeEngine.bind_expression()
method orTypeEngine.bind_processor()
method or equivalent, these functions will take effect at statement compilation/execution time when a literal value is passed, as in:# bound-value handling of MyStringType will be applied to the # literal value "some string" stmt = select(type_coerce("some string", MyStringType))
When using
type_coerce()
with composed expressions, note that parenthesis are not applied. Iftype_coerce()
is being used in an operator context where the parenthesis normally present from CAST are necessary, use theTypeCoerce.self_group()
method:>>> some_integer = column("someint", Integer) >>> some_string = column("somestr", String) >>> expr = type_coerce(some_integer + 5, String) + some_string >>> print(expr)
someint + :someint_1 || somestr>>> expr = type_coerce(some_integer + 5, String).self_group() + some_string >>> print(expr)(someint + :someint_1) || somestr- Parameters:
expression¶ – A SQL expression, such as a
ColumnElement
expression or a Python string which will be coerced into a bound literal value.type_¶ – A
TypeEngine
class or instance indicating the type to which the expression is coerced.
- class sqlalchemy.sql.expression.quoted_name¶
Represent a SQL identifier combined with quoting preferences.
quoted_name
is a Python unicode/str subclass which represents a particular identifier name along with aquote
flag. Thisquote
flag, when set toTrue
orFalse
, overrides automatic quoting behavior for this identifier in order to either unconditionally quote or to not quote the name. If left at its default ofNone
, quoting behavior is applied to the identifier on a per-backend basis based on an examination of the token itself.A
quoted_name
object withquote=True
is also prevented from being modified in the case of a so-called “name normalize” option. Certain database backends, such as Oracle, Firebird, and DB2 “normalize” case-insensitive names as uppercase. The SQLAlchemy dialects for these backends convert from SQLAlchemy’s lower-case-means-insensitive convention to the upper-case-means-insensitive conventions of those backends. Thequote=True
flag here will prevent this conversion from occurring to support an identifier that’s quoted as all lower case against such a backend.The
quoted_name
object is normally created automatically when specifying the name for key schema constructs such asTable
,Column
, and others. The class can also be passed explicitly as the name to any function that receives a name which can be quoted. Such as to use theEngine.has_table()
method with an unconditionally quoted name:from sqlalchemy import create_engine from sqlalchemy import inspect from sqlalchemy.sql import quoted_name engine = create_engine("oracle+cx_oracle://some_dsn") print(inspect(engine).has_table(quoted_name("some_table", True)))
The above logic will run the “has table” logic against the Oracle backend, passing the name exactly as
"some_table"
without converting to upper case.Changed in version 1.2: The
quoted_name
construct is now importable fromsqlalchemy.sql
, in addition to the previous location ofsqlalchemy.sql.elements
.Members
Class signature
class
sqlalchemy.sql.expression.quoted_name
(sqlalchemy.util.langhelpers.MemoizedSlots
,builtins.str
)-
attribute
sqlalchemy.sql.expression.quoted_name.
quote¶ whether the string should be unconditionally quoted
-
attribute
Column Element Modifier Constructors¶
Functions listed here are more commonly available as methods from any
ColumnElement
construct, for example, the
label()
function is usually invoked via the
ColumnElement.label()
method.
Object Name | Description |
---|---|
all_(expr) |
Produce an ALL expression. |
any_(expr) |
Produce an ANY expression. |
asc(column) |
Produce an ascending |
between(expr, lower_bound, upper_bound[, symmetric]) |
Produce a |
collate(expression, collation) |
Return the clause |
desc(column) |
Produce a descending |
funcfilter(func, *criterion) |
Produce a |
label(name, element[, type_]) |
Return a |
nulls_first(column) |
Produce the |
nulls_last(column) |
Produce the |
Synonym for the |
|
Legacy synonym for the |
|
over(element[, partition_by, order_by, range_, ...]) |
Produce an |
within_group(element, *order_by) |
Produce a |
- function sqlalchemy.sql.expression.all_(expr: _ColumnExpressionArgument[_T]) → CollectionAggregate[bool]¶
Produce an ALL expression.
For dialects such as that of PostgreSQL, this operator applies to usage of the
ARRAY
datatype, for that of MySQL, it may apply to a subquery. e.g.:# renders on PostgreSQL: # '5 = ALL (somearray)' expr = 5 == all_(mytable.c.somearray) # renders on MySQL: # '5 = ALL (SELECT value FROM table)' expr = 5 == all_(select(table.c.value))
Comparison to NULL may work using
None
:None == all_(mytable.c.somearray)
The any_() / all_() operators also feature a special “operand flipping” behavior such that if any_() / all_() are used on the left side of a comparison using a standalone operator such as
==
,!=
, etc. (not including operator methods such asColumnOperators.is_()
) the rendered expression is flipped:# would render '5 = ALL (column)` all_(mytable.c.column) == 5
Or with
None
, which note will not perform the usual step of rendering “IS” as is normally the case for NULL:# would render 'NULL = ALL(somearray)' all_(mytable.c.somearray) == None
Changed in version 1.4.26: repaired the use of any_() / all_() comparing to NULL on the right side to be flipped to the left.
The column-level
ColumnElement.all_()
method (not to be confused withARRAY
levelComparator.all()
) is shorthand forall_(col)
:5 == mytable.c.somearray.all_()
- function sqlalchemy.sql.expression.any_(expr: _ColumnExpressionArgument[_T]) → CollectionAggregate[bool]¶
Produce an ANY expression.
For dialects such as that of PostgreSQL, this operator applies to usage of the
ARRAY
datatype, for that of MySQL, it may apply to a subquery. e.g.:# renders on PostgreSQL: # '5 = ANY (somearray)' expr = 5 == any_(mytable.c.somearray) # renders on MySQL: # '5 = ANY (SELECT value FROM table)' expr = 5 == any_(select(table.c.value))
Comparison to NULL may work using
None
ornull()
:None == any_(mytable.c.somearray)
The any_() / all_() operators also feature a special “operand flipping” behavior such that if any_() / all_() are used on the left side of a comparison using a standalone operator such as
==
,!=
, etc. (not including operator methods such asColumnOperators.is_()
) the rendered expression is flipped:# would render '5 = ANY (column)` any_(mytable.c.column) == 5
Or with
None
, which note will not perform the usual step of rendering “IS” as is normally the case for NULL:# would render 'NULL = ANY(somearray)' any_(mytable.c.somearray) == None
Changed in version 1.4.26: repaired the use of any_() / all_() comparing to NULL on the right side to be flipped to the left.
The column-level
ColumnElement.any_()
method (not to be confused withARRAY
levelComparator.any()
) is shorthand forany_(col)
:5 = mytable.c.somearray.any_()
- function sqlalchemy.sql.expression.asc(column: _ColumnExpressionOrStrLabelArgument[_T]) → UnaryExpression[_T]¶
Produce an ascending
ORDER BY
clause element.e.g.:
from sqlalchemy import asc stmt = select(users_table).order_by(asc(users_table.c.name))
will produce SQL as:
SELECT id, name FROM user ORDER BY name ASC
The
asc()
function is a standalone version of theColumnElement.asc()
method available on all SQL expressions, e.g.:stmt = select(users_table).order_by(users_table.c.name.asc())
- Parameters:
column¶ – A
ColumnElement
(e.g. scalar SQL expression) with which to apply theasc()
operation.
- function sqlalchemy.sql.expression.between(expr: _ColumnExpressionOrLiteralArgument[_T], lower_bound: Any, upper_bound: Any, symmetric: bool = False) → BinaryExpression[bool]¶
Produce a
BETWEEN
predicate clause.E.g.:
from sqlalchemy import between stmt = select(users_table).where(between(users_table.c.id, 5, 7))
Would produce SQL resembling:
SELECT id, name FROM user WHERE id BETWEEN :id_1 AND :id_2
The
between()
function is a standalone version of theColumnElement.between()
method available on all SQL expressions, as in:stmt = select(users_table).where(users_table.c.id.between(5, 7))
All arguments passed to
between()
, including the left side column expression, are coerced from Python scalar values if a the value is not aColumnElement
subclass. For example, three fixed values can be compared as in:print(between(5, 3, 7))
Which would produce:
:param_1 BETWEEN :param_2 AND :param_3
- Parameters:
expr¶ – a column expression, typically a
ColumnElement
instance or alternatively a Python scalar expression to be coerced into a column expression, serving as the left side of theBETWEEN
expression.lower_bound¶ – a column or Python scalar expression serving as the lower bound of the right side of the
BETWEEN
expression.upper_bound¶ – a column or Python scalar expression serving as the upper bound of the right side of the
BETWEEN
expression.symmetric¶ – if True, will render “ BETWEEN SYMMETRIC “. Note that not all databases support this syntax.
See also
- function sqlalchemy.sql.expression.collate(expression: _ColumnExpressionArgument[str], collation: str) → BinaryExpression[str]¶
Return the clause
expression COLLATE collation
.e.g.:
collate(mycolumn, 'utf8_bin')
produces:
mycolumn COLLATE utf8_bin
The collation expression is also quoted if it is a case sensitive identifier, e.g. contains uppercase characters.
Changed in version 1.2: quoting is automatically applied to COLLATE expressions if they are case sensitive.
- function sqlalchemy.sql.expression.desc(column: _ColumnExpressionOrStrLabelArgument[_T]) → UnaryExpression[_T]¶
Produce a descending
ORDER BY
clause element.e.g.:
from sqlalchemy import desc stmt = select(users_table).order_by(desc(users_table.c.name))
will produce SQL as:
SELECT id, name FROM user ORDER BY name DESC
The
desc()
function is a standalone version of theColumnElement.desc()
method available on all SQL expressions, e.g.:stmt = select(users_table).order_by(users_table.c.name.desc())
- Parameters:
column¶ – A
ColumnElement
(e.g. scalar SQL expression) with which to apply thedesc()
operation.
- function sqlalchemy.sql.expression.funcfilter(func: FunctionElement[_T], *criterion: _ColumnExpressionArgument[bool]) → FunctionFilter[_T]¶
Produce a
FunctionFilter
object against a function.Used against aggregate and window functions, for database backends that support the “FILTER” clause.
E.g.:
from sqlalchemy import funcfilter funcfilter(func.count(1), MyClass.name == 'some name')
Would produce “COUNT(1) FILTER (WHERE myclass.name = ‘some name’)”.
This function is also available from the
func
construct itself via theFunctionElement.filter()
method.
- function sqlalchemy.sql.expression.label(name: str, element: _ColumnExpressionArgument[_T], type_: _TypeEngineArgument[_T] | None = None) → Label[_T]¶
Return a
Label
object for the givenColumnElement
.A label changes the name of an element in the columns clause of a
SELECT
statement, typically via theAS
SQL keyword.This functionality is more conveniently available via the
ColumnElement.label()
method onColumnElement
.- Parameters:
name¶ – label name
obj¶ – a
ColumnElement
.
- function sqlalchemy.sql.expression.nulls_first(column: _ColumnExpressionArgument[_T]) → UnaryExpression[_T]¶
Produce the
NULLS FIRST
modifier for anORDER BY
expression.nulls_first()
is intended to modify the expression produced byasc()
ordesc()
, and indicates how NULL values should be handled when they are encountered during ordering:from sqlalchemy import desc, nulls_first stmt = select(users_table).order_by( nulls_first(desc(users_table.c.name)))
The SQL expression from the above would resemble:
SELECT id, name FROM user ORDER BY name DESC NULLS FIRST
Like
asc()
anddesc()
,nulls_first()
is typically invoked from the column expression itself usingColumnElement.nulls_first()
, rather than as its standalone function version, as in:stmt = select(users_table).order_by( users_table.c.name.desc().nulls_first())
Changed in version 1.4:
nulls_first()
is renamed fromnullsfirst()
in previous releases. The previous name remains available for backwards compatibility.
- function sqlalchemy.sql.expression.nullsfirst()¶
Synonym for the
nulls_first()
function.Changed in version 2.0.5: restored missing legacy symbol
nullsfirst()
.
- function sqlalchemy.sql.expression.nulls_last(column: _ColumnExpressionArgument[_T]) → UnaryExpression[_T]¶
Produce the
NULLS LAST
modifier for anORDER BY
expression.nulls_last()
is intended to modify the expression produced byasc()
ordesc()
, and indicates how NULL values should be handled when they are encountered during ordering:from sqlalchemy import desc, nulls_last stmt = select(users_table).order_by( nulls_last(desc(users_table.c.name)))
The SQL expression from the above would resemble:
SELECT id, name FROM user ORDER BY name DESC NULLS LAST
Like
asc()
anddesc()
,nulls_last()
is typically invoked from the column expression itself usingColumnElement.nulls_last()
, rather than as its standalone function version, as in:stmt = select(users_table).order_by( users_table.c.name.desc().nulls_last())
Changed in version 1.4:
nulls_last()
is renamed fromnullslast()
in previous releases. The previous name remains available for backwards compatibility.
- function sqlalchemy.sql.expression.nullslast()¶
Legacy synonym for the
nulls_last()
function.Changed in version 2.0.5: restored missing legacy symbol
nullslast()
.
- function sqlalchemy.sql.expression.over(element: FunctionElement[_T], partition_by: _ByArgument | None = None, order_by: _ByArgument | None = None, range_: typing_Tuple[int | None, int | None] | None = None, rows: typing_Tuple[int | None, int | None] | None = None) → Over[_T]¶
Produce an
Over
object against a function.Used against aggregate or so-called “window” functions, for database backends that support window functions.
over()
is usually called using theFunctionElement.over()
method, e.g.:func.row_number().over(order_by=mytable.c.some_column)
Would produce:
ROW_NUMBER() OVER(ORDER BY some_column)
Ranges are also possible using the
over.range_
andover.rows
parameters. These mutually-exclusive parameters each accept a 2-tuple, which contains a combination of integers and None:func.row_number().over( order_by=my_table.c.some_column, range_=(None, 0))
The above would produce:
ROW_NUMBER() OVER(ORDER BY some_column RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
A value of
None
indicates “unbounded”, a value of zero indicates “current row”, and negative / positive integers indicate “preceding” and “following”:RANGE BETWEEN 5 PRECEDING AND 10 FOLLOWING:
func.row_number().over(order_by='x', range_=(-5, 10))
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW:
func.row_number().over(order_by='x', rows=(None, 0))
RANGE BETWEEN 2 PRECEDING AND UNBOUNDED FOLLOWING:
func.row_number().over(order_by='x', range_=(-2, None))
RANGE BETWEEN 1 FOLLOWING AND 3 FOLLOWING:
func.row_number().over(order_by='x', range_=(1, 3))
- Parameters:
element¶ – a
FunctionElement
,WithinGroup
, or other compatible construct.partition_by¶ – a column element or string, or a list of such, that will be used as the PARTITION BY clause of the OVER construct.
order_by¶ – a column element or string, or a list of such, that will be used as the ORDER BY clause of the OVER construct.
range_¶ – optional range clause for the window. This is a tuple value which can contain integer values or
None
, and will render a RANGE BETWEEN PRECEDING / FOLLOWING clause.rows¶ – optional rows clause for the window. This is a tuple value which can contain integer values or None, and will render a ROWS BETWEEN PRECEDING / FOLLOWING clause.
This function is also available from the
func
construct itself via theFunctionElement.over()
method.
- function sqlalchemy.sql.expression.within_group(element: FunctionElement[_T], *order_by: _ColumnExpressionArgument[Any]) → WithinGroup[_T]¶
Produce a
WithinGroup
object against a function.Used against so-called “ordered set aggregate” and “hypothetical set aggregate” functions, including
percentile_cont
,rank
,dense_rank
, etc.within_group()
is usually called using theFunctionElement.within_group()
method, e.g.:from sqlalchemy import within_group stmt = select( department.c.id, func.percentile_cont(0.5).within_group( department.c.salary.desc() ) )
The above statement would produce SQL similar to
SELECT department.id, percentile_cont(0.5) WITHIN GROUP (ORDER BY department.salary DESC)
.- Parameters:
element¶ – a
FunctionElement
construct, typically generated byfunc
.*order_by¶ – one or more column elements that will be used as the ORDER BY clause of the WITHIN GROUP construct.
Column Element Class Documentation¶
The classes here are generated using the constructors listed at Column Element Foundational Constructors and Column Element Modifier Constructors.
Object Name | Description |
---|---|
Represent an expression that is |
|
Represent a “bound expression”. |
|
Represent a |
|
Represent a |
|
Describe a list of clauses, separated by an operator. |
|
Represents a column expression from any textual string. |
|
Collection of |
|
Represent a column-oriented SQL expression suitable for usage in the “columns” clause, WHERE clause etc. of a statement. |
|
General purpose “column expression” argument. |
|
Defines boolean, comparison, and other operators for
|
|
Represent a SQL EXTRACT clause, |
|
Represent the |
|
Represent a function FILTER clause. |
|
Represents a column label (AS). |
|
Represent the NULL keyword in a SQL statement. |
|
Base of comparison and logical operators. |
|
Represent an OVER clause. |
|
A type that may be used to indicate any SQL column element or object that acts in place of one. |
|
Represent a literal SQL text fragment. |
|
Represent the |
|
Represent a TRY_CAST expression. |
|
Represent a SQL tuple. |
|
Represent a Python-side type-coercion wrapper. |
|
Define a ‘unary’ expression. |
|
Represent a WITHIN GROUP (ORDER BY) clause. |
|
Mixin that defines a |
- class sqlalchemy.sql.expression.BinaryExpression¶
Represent an expression that is
LEFT <operator> RIGHT
.A
BinaryExpression
is generated automatically whenever two column expressions are used in a Python binary expression:>>> from sqlalchemy.sql import column >>> column('a') + column('b') <sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0> >>> print(column('a') + column('b'))
a + bClass signature
class
sqlalchemy.sql.expression.BinaryExpression
(sqlalchemy.sql.expression.OperatorExpression
)
- class sqlalchemy.sql.expression.BindParameter¶
Represent a “bound expression”.
BindParameter
is invoked explicitly using thebindparam()
function, as in:from sqlalchemy import bindparam stmt = select(users_table).where( users_table.c.name == bindparam("username") )
Detailed discussion of how
BindParameter
is used is atbindparam()
.See also
Class signature
class
sqlalchemy.sql.expression.BindParameter
(sqlalchemy.sql.roles.InElementRole
,sqlalchemy.sql.expression.KeyedColumnElement
)-
attribute
sqlalchemy.sql.expression.BindParameter.
effective_value¶ Return the value of this bound parameter, taking into account if the
callable
parameter was set.The
callable
value will be evaluated and returned if present, elsevalue
.
-
attribute
sqlalchemy.sql.expression.BindParameter.
inherit_cache: bool | None = True¶ Indicate if this
HasCacheKey
instance should make use of the cache key generation scheme used by its immediate superclass.The attribute defaults to
None
, which indicates that a construct has not yet taken into account whether or not its appropriate for it to participate in caching; this is functionally equivalent to setting the value toFalse
, except that a warning is also emitted.This flag can be set to
True
on a particular class, if the SQL that corresponds to the object does not change based on attributes which are local to this class, and not its superclass.See also
Enabling Caching Support for Custom Constructs - General guideslines for setting the
HasCacheKey.inherit_cache
attribute for third-party or user defined SQL constructs.
-
method
sqlalchemy.sql.expression.BindParameter.
render_literal_execute() → BindParameter[_T]¶ Produce a copy of this bound parameter that will enable the
BindParameter.literal_execute
flag.The
BindParameter.literal_execute
flag will have the effect of the parameter rendered in the compiled SQL string using[POSTCOMPILE]
form, which is a special form that is converted to be a rendering of the literal value of the parameter at SQL execution time. The rationale is to support caching of SQL statement strings that can embed per-statement literal values, such as LIMIT and OFFSET parameters, in the final SQL string that is passed to the DBAPI. Dialects in particular may want to use this method within custom compilation schemes.New in version 1.4.5.
See also
-
attribute
- class sqlalchemy.sql.expression.Case¶
Represent a
CASE
expression.Case
is produced using thecase()
factory function, as in:from sqlalchemy import case stmt = select(users_table). where( case( (users_table.c.name == 'wendy', 'W'), (users_table.c.name == 'jack', 'J'), else_='E' ) )
Details on
Case
usage is atcase()
.See also
Class signature
class
sqlalchemy.sql.expression.Case
(sqlalchemy.sql.expression.ColumnElement
)
- class sqlalchemy.sql.expression.Cast¶
Represent a
CAST
expression.Cast
is produced using thecast()
factory function, as in:from sqlalchemy import cast, Numeric stmt = select(cast(product_table.c.unit_price, Numeric(10, 4)))
Details on
Cast
usage is atcast()
.See also
type_coerce()
- an alternative to CAST that coerces the type on the Python side only, which is often sufficient to generate the correct SQL and data coercion.Class signature
class
sqlalchemy.sql.expression.Cast
(sqlalchemy.sql.expression.WrapsColumnExpression
)
- class sqlalchemy.sql.expression.ClauseList¶
Describe a list of clauses, separated by an operator.
By default, is comma-separated, such as a column listing.
Members
Class signature
class
sqlalchemy.sql.expression.ClauseList
(sqlalchemy.sql.roles.InElementRole
,sqlalchemy.sql.roles.OrderByRole
,sqlalchemy.sql.roles.ColumnsClauseRole
,sqlalchemy.sql.roles.DMLColumnRole
,sqlalchemy.sql.expression.DQLDMLClauseElement
)-
method
sqlalchemy.sql.expression.ClauseList.
self_group(against: OperatorType | None = None) → Self | Grouping[Any]¶ Apply a ‘grouping’ to this
ClauseElement
.This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by
select()
constructs when placed into the FROM clause of anotherselect()
. (Note that subqueries should be normally created using theSelect.alias()
method, as many platforms require nested SELECT statements to be named).As expressions are composed together, the application of
self_group()
is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression likex OR (y AND z)
- AND takes precedence over OR.The base
self_group()
method ofClauseElement
just returns self.
-
method
- class sqlalchemy.sql.expression.ColumnClause¶
Represents a column expression from any textual string.
The
ColumnClause
, a lightweight analogue to theColumn
class, is typically invoked using thecolumn()
function, as in:from sqlalchemy import column id, name = column("id"), column("name") stmt = select(id, name).select_from("user")
The above statement would produce SQL like:
SELECT id, name FROM user
ColumnClause
is the immediate superclass of the schema-specificColumn
object. While theColumn
class has all the same capabilities asColumnClause
, theColumnClause
class is usable by itself in those cases where behavioral requirements are limited to simple SQL expression generation. The object has none of the associations with schema-level metadata or with execution-time behavior thatColumn
does, so in that sense is a “lightweight” version ofColumn
.Full details on
ColumnClause
usage is atcolumn()
.Members
Class signature
class
sqlalchemy.sql.expression.ColumnClause
(sqlalchemy.sql.roles.DDLReferredColumnRole
,sqlalchemy.sql.roles.LabeledColumnExprRole
,sqlalchemy.sql.roles.StrAsPlainColumnRole
,sqlalchemy.sql.expression.Immutable
,sqlalchemy.sql.expression.NamedColumn
)-
method
sqlalchemy.sql.expression.ColumnClause.
get_children(*, column_tables=False, **kw)¶ Return immediate child
HasTraverseInternals
elements of thisHasTraverseInternals
.This is used for visit traversal.
**kw may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).
-
method
- class sqlalchemy.sql.expression.ColumnCollection¶
Collection of
ColumnElement
instances, typically forFromClause
objects.The
ColumnCollection
object is most commonly available as theTable.c
orTable.columns
collection on theTable
object, introduced at Accessing Tables and Columns.The
ColumnCollection
has both mapping- and sequence- like behaviors. AColumnCollection
usually storesColumn
objects, which are then accessible both via mapping style access as well as attribute access style.To access
Column
objects using ordinary attribute-style access, specify the name like any other object attribute, such as below a column namedemployee_name
is accessed:>>> employee_table.c.employee_name
To access columns that have names with special characters or spaces, index-style access is used, such as below which illustrates a column named
employee ' payment
is accessed:>>> employee_table.c["employee ' payment"]
As the
ColumnCollection
object provides a Python dictionary interface, common dictionary method names likeColumnCollection.keys()
,ColumnCollection.values()
, andColumnCollection.items()
are available, which means that database columns that are keyed under these names also need to use indexed access:>>> employee_table.c["values"]
The name for which a
Column
would be present is normally that of theColumn.key
parameter. In some contexts, such as aSelect
object that uses a label style set using theSelect.set_label_style()
method, a column of a certain key may instead be represented under a particular label name such astablename_columnname
:>>> from sqlalchemy import select, column, table >>> from sqlalchemy import LABEL_STYLE_TABLENAME_PLUS_COL >>> t = table("t", column("c")) >>> stmt = select(t).set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL) >>> subq = stmt.subquery() >>> subq.c.t_c <sqlalchemy.sql.elements.ColumnClause at 0x7f59dcf04fa0; t_c>
ColumnCollection
also indexes the columns in order and allows them to be accessible by their integer position:>>> cc[0] Column('x', Integer(), table=None) >>> cc[1] Column('y', Integer(), table=None)
New in version 1.4:
ColumnCollection
allows integer-based index access to the collection.Iterating the collection yields the column expressions in order:
>>> list(cc) [Column('x', Integer(), table=None), Column('y', Integer(), table=None)]
The base
ColumnCollection
object can store duplicates, which can mean either two columns with the same key, in which case the column returned by key access is arbitrary:>>> x1, x2 = Column('x', Integer), Column('x', Integer) >>> cc = ColumnCollection(columns=[(x1.name, x1), (x2.name, x2)]) >>> list(cc) [Column('x', Integer(), table=None), Column('x', Integer(), table=None)] >>> cc['x'] is x1 False >>> cc['x'] is x2 True
Or it can also mean the same column multiple times. These cases are supported as
ColumnCollection
is used to represent the columns in a SELECT statement which may include duplicates.A special subclass
DedupeColumnCollection
exists which instead maintains SQLAlchemy’s older behavior of not allowing duplicates; this collection is used for schema level objects likeTable
andPrimaryKeyConstraint
where this deduping is helpful. TheDedupeColumnCollection
class also has additional mutation methods as the schema constructs have more use cases that require removal and replacement of columns.Changed in version 1.4:
ColumnCollection
now stores duplicate column keys as well as the same column in multiple positions. TheDedupeColumnCollection
class is added to maintain the former behavior in those cases where deduplication as well as additional replace/remove operations are needed.Members
add(), as_readonly(), clear(), compare(), contains_column(), corresponding_column(), get(), items(), keys(), update(), values()
Class signature
class
sqlalchemy.sql.expression.ColumnCollection
(typing.Generic
)-
method
sqlalchemy.sql.expression.ColumnCollection.
add(column: ColumnElement[Any], key: _COLKEY | None = None) → None¶ Add a column to this
ColumnCollection
.Note
This method is not normally used by user-facing code, as the
ColumnCollection
is usually part of an existing object such as aTable
. To add aColumn
to an existingTable
object, use theTable.append_column()
method.
-
method
sqlalchemy.sql.expression.ColumnCollection.
as_readonly() → ReadOnlyColumnCollection[_COLKEY, _COL_co]¶ Return a “read only” form of this
ColumnCollection
.
-
method
sqlalchemy.sql.expression.ColumnCollection.
clear() → NoReturn¶ Dictionary clear() is not implemented for
ColumnCollection
.
-
method
sqlalchemy.sql.expression.ColumnCollection.
compare(other: ColumnCollection[Any, Any]) → bool¶ Compare this
ColumnCollection
to another based on the names of the keys
-
method
sqlalchemy.sql.expression.ColumnCollection.
contains_column(col: ColumnElement[Any]) → bool¶ Checks if a column object exists in this collection
-
method
sqlalchemy.sql.expression.ColumnCollection.
corresponding_column(column: _COL, require_embedded: bool = False) → _COL | _COL_co | None¶ Given a
ColumnElement
, return the exportedColumnElement
object from thisColumnCollection
which corresponds to that originalColumnElement
via a common ancestor column.- Parameters:
column¶ – the target
ColumnElement
to be matched.require_embedded¶ – only return corresponding columns for the given
ColumnElement
, if the givenColumnElement
is actually present within a sub-element of thisSelectable
. Normally the column will match if it merely shares a common ancestor with one of the exported columns of thisSelectable
.
See also
Selectable.corresponding_column()
- invokes this method against the collection returned bySelectable.exported_columns
.Changed in version 1.4: the implementation for
corresponding_column
was moved onto theColumnCollection
itself.
-
method
sqlalchemy.sql.expression.ColumnCollection.
get(key: str, default: _COL | None = None) → _COL | _COL_co | None¶ Get a
ColumnClause
orColumn
object based on a string key name from thisColumnCollection
.
-
method
sqlalchemy.sql.expression.ColumnCollection.
items() → List[Tuple[_COLKEY, _COL_co]]¶ Return a sequence of (key, column) tuples for all columns in this collection each consisting of a string key name and a
ColumnClause
orColumn
object.
-
method
sqlalchemy.sql.expression.ColumnCollection.
keys() → List[_COLKEY]¶ Return a sequence of string key names for all columns in this collection.
-
method
sqlalchemy.sql.expression.ColumnCollection.
update(iter_: Any) → NoReturn¶ Dictionary update() is not implemented for
ColumnCollection
.
-
method
sqlalchemy.sql.expression.ColumnCollection.
values() → List[_COL_co]¶ Return a sequence of
ColumnClause
orColumn
objects for all columns in this collection.
-
method
- class sqlalchemy.sql.expression.ColumnElement¶
Represent a column-oriented SQL expression suitable for usage in the “columns” clause, WHERE clause etc. of a statement.
While the most familiar kind of
ColumnElement
is theColumn
object,ColumnElement
serves as the basis for any unit that may be present in a SQL expression, including the expressions themselves, SQL functions, bound parameters, literal expressions, keywords such asNULL
, etc.ColumnElement
is the ultimate base class for all such elements.A wide variety of SQLAlchemy Core functions work at the SQL expression level, and are intended to accept instances of
ColumnElement
as arguments. These functions will typically document that they accept a “SQL expression” as an argument. What this means in terms of SQLAlchemy usually refers to an input which is either already in the form of aColumnElement
object, or a value which can be coerced into one. The coercion rules followed by most, but not all, SQLAlchemy Core functions with regards to SQL expressions are as follows:a literal Python value, such as a string, integer or floating point value, boolean, datetime,
Decimal
object, or virtually any other Python object, will be coerced into a “literal bound value”. This generally means that abindparam()
will be produced featuring the given value embedded into the construct; the resultingBindParameter
object is an instance ofColumnElement
. The Python value will ultimately be sent to the DBAPI at execution time as a parameterized argument to theexecute()
orexecutemany()
methods, after SQLAlchemy type-specific converters (e.g. those provided by any associatedTypeEngine
objects) are applied to the value.any special object value, typically ORM-level constructs, which feature an accessor called
__clause_element__()
. The Core expression system looks for this method when an object of otherwise unknown type is passed to a function that is looking to coerce the argument into aColumnElement
and sometimes aSelectBase
expression. It is used within the ORM to convert from ORM-specific objects like mapped classes and mapped attributes into Core expression objects.The Python
None
value is typically interpreted asNULL
, which in SQLAlchemy Core produces an instance ofnull()
.
A
ColumnElement
provides the ability to generate newColumnElement
objects using Python expressions. This means that Python operators such as==
,!=
and<
are overloaded to mimic SQL operations, and allow the instantiation of furtherColumnElement
instances which are composed from other, more fundamentalColumnElement
objects. For example, twoColumnClause
objects can be added together with the addition operator+
to produce aBinaryExpression
. BothColumnClause
andBinaryExpression
are subclasses ofColumnElement
:>>> from sqlalchemy.sql import column >>> column('a') + column('b') <sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0> >>> print(column('a') + column('b'))
a + bMembers
__eq__(), __le__(), __lt__(), __ne__(), all_(), allows_lambda, anon_key_label, anon_label, any_(), asc(), base_columns, between(), bitwise_and(), bitwise_lshift(), bitwise_not(), bitwise_or(), bitwise_rshift(), bitwise_xor(), bool_op(), cast(), collate(), comparator, compare(), compile(), concat(), contains(), desc(), description, distinct(), endswith(), entity_namespace, expression, foreign_keys, get_children(), icontains(), iendswith(), ilike(), in_(), inherit_cache, is_(), is_clause_element, is_distinct_from(), is_dml, is_not(), is_not_distinct_from(), is_selectable, isnot(), isnot_distinct_from(), istartswith(), key, label(), like(), match(), negation_clause, not_ilike(), not_in(), not_like(), notilike(), notin_(), notlike(), nulls_first(), nulls_last(), nullsfirst(), nullslast(), op(), operate(), params(), primary_key, proxy_set, regexp_match(), regexp_replace(), reverse_operate(), self_group(), shares_lineage(), startswith(), stringify_dialect, supports_execution, timetuple, type, unique_params(), uses_inspection
Class signature
class
sqlalchemy.sql.expression.ColumnElement
(sqlalchemy.sql.roles.ColumnArgumentOrKeyRole
,sqlalchemy.sql.roles.StatementOptionRole
,sqlalchemy.sql.roles.WhereHavingRole
,sqlalchemy.sql.roles.BinaryElementRole
,sqlalchemy.sql.roles.OrderByRole
,sqlalchemy.sql.roles.ColumnsClauseRole
,sqlalchemy.sql.roles.LimitOffsetRole
,sqlalchemy.sql.roles.DMLColumnRole
,sqlalchemy.sql.roles.DDLConstraintColumnRole
,sqlalchemy.sql.roles.DDLExpressionRole
,sqlalchemy.sql.expression.SQLColumnExpression
,sqlalchemy.sql.expression.DQLDMLClauseElement
)-
method
sqlalchemy.sql.expression.ColumnElement.
__eq__(other: Any) → ColumnOperators¶ inherited from the
sqlalchemy.sql.expression.ColumnOperators.__eq__
method ofColumnOperators
Implement the
==
operator.In a column context, produces the clause
a = b
. If the target isNone
, producesa IS NULL
.
-
method
sqlalchemy.sql.expression.ColumnElement.
__le__(other: Any) → ColumnOperators¶ inherited from the
sqlalchemy.sql.expression.ColumnOperators.__le__
method ofColumnOperators
Implement the
<=
operator.In a column context, produces the clause
a <= b
.
-
method
sqlalchemy.sql.expression.ColumnElement.
__lt__(other: Any) → ColumnOperators¶ inherited from the
sqlalchemy.sql.expression.ColumnOperators.__lt__
method ofColumnOperators
Implement the
<
operator.In a column context, produces the clause
a < b
.
-
method
sqlalchemy.sql.expression.ColumnElement.
__ne__(other: Any) → ColumnOperators¶ inherited from the
sqlalchemy.sql.expression.ColumnOperators.__ne__
method ofColumnOperators
Implement the
!=
operator.In a column context, produces the clause
a != b
. If the target isNone
, producesa IS NOT NULL
.
-
method
sqlalchemy.sql.expression.ColumnElement.
all_() → ColumnOperators¶ inherited from the
ColumnOperators.all_()
method ofColumnOperators
Produce an
all_()
clause against the parent object.See the documentation for
all_()
for examples.Note
be sure to not confuse the newer
ColumnOperators.all_()
method with the legacy version of this method, theComparator.all()
method that’s specific toARRAY
, which uses a different calling style.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
allows_lambda = True¶
-
attribute
sqlalchemy.sql.expression.ColumnElement.
anon_key_label¶ Deprecated since version 1.4: The
ColumnElement.anon_key_label
attribute is now private, and the public accessor is deprecated.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
anon_label¶ Deprecated since version 1.4: The
ColumnElement.anon_label
attribute is now private, and the public accessor is deprecated.
-
method
sqlalchemy.sql.expression.ColumnElement.
any_() → ColumnOperators¶ inherited from the
ColumnOperators.any_()
method ofColumnOperators
Produce an
any_()
clause against the parent object.See the documentation for
any_()
for examples.Note
be sure to not confuse the newer
ColumnOperators.any_()
method with the legacy version of this method, theComparator.any()
method that’s specific toARRAY
, which uses a different calling style.
-
method
sqlalchemy.sql.expression.ColumnElement.
asc() → ColumnOperators¶ inherited from the
ColumnOperators.asc()
method ofColumnOperators
Produce a
asc()
clause against the parent object.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
base_columns¶
-
method
sqlalchemy.sql.expression.ColumnElement.
between(cleft: Any, cright: Any, symmetric: bool = False) → ColumnOperators¶ inherited from the
ColumnOperators.between()
method ofColumnOperators
Produce a
between()
clause against the parent object, given the lower and upper range.
-
method
sqlalchemy.sql.expression.ColumnElement.
bitwise_and(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.bitwise_and()
method ofColumnOperators
Produce a bitwise AND operation, typically via the
&
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
bitwise_lshift(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.bitwise_lshift()
method ofColumnOperators
Produce a bitwise LSHIFT operation, typically via the
<<
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
bitwise_not() → ColumnOperators¶ inherited from the
ColumnOperators.bitwise_not()
method ofColumnOperators
Produce a bitwise NOT operation, typically via the
~
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
bitwise_or(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.bitwise_or()
method ofColumnOperators
Produce a bitwise OR operation, typically via the
|
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
bitwise_rshift(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.bitwise_rshift()
method ofColumnOperators
Produce a bitwise RSHIFT operation, typically via the
>>
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
bitwise_xor(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.bitwise_xor()
method ofColumnOperators
Produce a bitwise XOR operation, typically via the
^
operator, or#
for PostgreSQL.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
bool_op(opstring: str, precedence: int = 0, python_impl: Callable[[...], Any] | None = None) → Callable[[Any], Operators]¶ inherited from the
Operators.bool_op()
method ofOperators
Return a custom boolean operator.
This method is shorthand for calling
Operators.op()
and passing theOperators.op.is_comparison
flag with True. A key advantage to usingOperators.bool_op()
is that when using column constructs, the “boolean” nature of the returned expression will be present for PEP 484 purposes.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
cast(type_: _TypeEngineArgument[_OPT]) → Cast[_OPT]¶ Produce a type cast, i.e.
CAST(<expression> AS <type>)
.This is a shortcut to the
cast()
function.
-
method
sqlalchemy.sql.expression.ColumnElement.
collate(collation: str) → ColumnOperators¶ inherited from the
ColumnOperators.collate()
method ofColumnOperators
Produce a
collate()
clause against the parent object, given the collation string.See also
-
attribute
sqlalchemy.sql.expression.ColumnElement.
comparator¶
-
method
sqlalchemy.sql.expression.ColumnElement.
compare(other: ClauseElement, **kw: Any) → bool¶ inherited from the
ClauseElement.compare()
method ofClauseElement
Compare this
ClauseElement
to the givenClauseElement
.Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass
compare()
methods and may be used to modify the criteria for comparison (seeColumnElement
).
-
method
sqlalchemy.sql.expression.ColumnElement.
compile(bind: _HasDialect | None = None, dialect: Dialect | None = None, **kw: Any) → Compiled¶ inherited from the
CompilerElement.compile()
method ofCompilerElement
Compile this SQL expression.
The return value is a
Compiled
object. Callingstr()
orunicode()
on the returned value will yield a string representation of the result. TheCompiled
object also can return a dictionary of bind parameter names and values using theparams
accessor.- Parameters:
bind¶ – An
Connection
orEngine
which can provide aDialect
in order to generate aCompiled
object. If thebind
anddialect
parameters are both omitted, a default SQL compiler is used.column_keys¶ – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If
None
, all columns from the target table object are rendered.dialect¶ – A
Dialect
instance which can generate aCompiled
object. This argument takes precedence over thebind
argument.compile_kwargs¶ –
optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the
literal_binds
flag through:from sqlalchemy.sql import table, column, select t = table('t', column('x')) s = select(t).where(t.c.x == 5) print(s.compile(compile_kwargs={"literal_binds": True}))
-
method
sqlalchemy.sql.expression.ColumnElement.
concat(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.concat()
method ofColumnOperators
Implement the ‘concat’ operator.
In a column context, produces the clause
a || b
, or uses theconcat()
operator on MySQL.
-
method
sqlalchemy.sql.expression.ColumnElement.
contains(other: Any, **kw: Any) → ColumnOperators¶ inherited from the
ColumnOperators.contains()
method ofColumnOperators
Implement the ‘contains’ operator.
Produces a LIKE expression that tests against a match for the middle of a string value:
column LIKE '%' || <other> || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.contains("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.contains.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.contains.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.contains.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.contains("foo%bar", autoescape=True)
Will render as:
somecolumn LIKE '%' || :param || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.contains("foo/%bar", escape="^")
Will render as:
somecolumn LIKE '%' || :param || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.contains.autoescape
:somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
-
method
sqlalchemy.sql.expression.ColumnElement.
desc() → ColumnOperators¶ inherited from the
ColumnOperators.desc()
method ofColumnOperators
Produce a
desc()
clause against the parent object.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
description¶ inherited from the
ClauseElement.description
attribute ofClauseElement
-
method
sqlalchemy.sql.expression.ColumnElement.
distinct() → ColumnOperators¶ inherited from the
ColumnOperators.distinct()
method ofColumnOperators
Produce a
distinct()
clause against the parent object.
-
method
sqlalchemy.sql.expression.ColumnElement.
endswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ inherited from the
ColumnOperators.endswith()
method ofColumnOperators
Implement the ‘endswith’ operator.
Produces a LIKE expression that tests against a match for the end of a string value:
column LIKE '%' || <other>
E.g.:
stmt = select(sometable).\ where(sometable.c.column.endswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.endswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.endswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.endswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.endswith("foo%bar", autoescape=True)
Will render as:
somecolumn LIKE '%' || :param ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.endswith("foo/%bar", escape="^")
Will render as:
somecolumn LIKE '%' || :param ESCAPE '^'
The parameter may also be combined with
ColumnOperators.endswith.autoescape
:somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
entity_namespace¶ inherited from the
ClauseElement.entity_namespace
attribute ofClauseElement
-
attribute
sqlalchemy.sql.expression.ColumnElement.
expression¶ Return a column expression.
Part of the inspection interface; returns self.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
foreign_keys: AbstractSet[ForeignKey] = frozenset({})¶
-
method
sqlalchemy.sql.expression.ColumnElement.
get_children(*, omit_attrs: Tuple[str, ...] = (), **kw: Any) → Iterable[HasTraverseInternals]¶ inherited from the
HasTraverseInternals.get_children()
method ofHasTraverseInternals
Return immediate child
HasTraverseInternals
elements of thisHasTraverseInternals
.This is used for visit traversal.
**kw may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).
-
method
sqlalchemy.sql.expression.ColumnElement.
icontains(other: Any, **kw: Any) → ColumnOperators¶ inherited from the
ColumnOperators.icontains()
method ofColumnOperators
Implement the
icontains
operator, e.g. case insensitive version ofColumnOperators.contains()
.Produces a LIKE expression that tests against an insensitive match for the middle of a string value:
lower(column) LIKE '%' || lower(<other>) || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.icontains("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.icontains.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.icontains.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.icontains.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.icontains("foo%bar", autoescape=True)
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.icontains("foo/%bar", escape="^")
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.contains.autoescape
:somecolumn.icontains("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
iendswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ inherited from the
ColumnOperators.iendswith()
method ofColumnOperators
Implement the
iendswith
operator, e.g. case insensitive version ofColumnOperators.endswith()
.Produces a LIKE expression that tests against an insensitive match for the end of a string value:
lower(column) LIKE '%' || lower(<other>)
E.g.:
stmt = select(sometable).\ where(sometable.c.column.iendswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.iendswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.iendswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.iendswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.iendswith("foo%bar", autoescape=True)
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.iendswith("foo/%bar", escape="^")
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '^'
The parameter may also be combined with
ColumnOperators.iendswith.autoescape
:somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
ilike(other: Any, escape: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.ilike()
method ofColumnOperators
Implement the
ilike
operator, e.g. case insensitive LIKE.In a column context, produces an expression either of the form:
lower(a) LIKE lower(other)
Or on backends that support the ILIKE operator:
a ILIKE other
E.g.:
stmt = select(sometable).\ where(sometable.c.column.ilike("%foobar%"))
- Parameters:
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
in_(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.in_()
method ofColumnOperators
Implement the
in
operator.In a column context, produces the clause
column IN <other>
.The given parameter
other
may be:A list of literal values, e.g.:
stmt.where(column.in_([1, 2, 3]))
In this calling form, the list of items is converted to a set of bound parameters the same length as the list given:
WHERE COL IN (?, ?, ?)
A list of tuples may be provided if the comparison is against a
tuple_()
containing multiple expressions:from sqlalchemy import tuple_ stmt.where(tuple_(col1, col2).in_([(1, 10), (2, 20), (3, 30)]))
An empty list, e.g.:
stmt.where(column.in_([]))
In this calling form, the expression renders an “empty set” expression. These expressions are tailored to individual backends and are generally trying to get an empty SELECT statement as a subquery. Such as on SQLite, the expression is:
WHERE col IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)
Changed in version 1.4: empty IN expressions now use an execution-time generated SELECT subquery in all cases.
A bound parameter, e.g.
bindparam()
, may be used if it includes thebindparam.expanding
flag:stmt.where(column.in_(bindparam('value', expanding=True)))
In this calling form, the expression renders a special non-SQL placeholder expression that looks like:
WHERE COL IN ([EXPANDING_value])
This placeholder expression is intercepted at statement execution time to be converted into the variable number of bound parameter form illustrated earlier. If the statement were executed as:
connection.execute(stmt, {"value": [1, 2, 3]})
The database would be passed a bound parameter for each value:
WHERE COL IN (?, ?, ?)
New in version 1.2: added “expanding” bound parameters
If an empty list is passed, a special “empty list” expression, which is specific to the database in use, is rendered. On SQLite this would be:
WHERE COL IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)
New in version 1.3: “expanding” bound parameters now support empty lists
a
select()
construct, which is usually a correlated scalar select:stmt.where( column.in_( select(othertable.c.y). where(table.c.x == othertable.c.x) ) )
In this calling form,
ColumnOperators.in_()
renders as given:WHERE COL IN (SELECT othertable.y FROM othertable WHERE othertable.x = table.x)
- Parameters:
other¶ – a list of literals, a
select()
construct, or abindparam()
construct that includes thebindparam.expanding
flag set to True.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
inherit_cache: bool | None = None¶ inherited from the
HasCacheKey.inherit_cache
attribute ofHasCacheKey
Indicate if this
HasCacheKey
instance should make use of the cache key generation scheme used by its immediate superclass.The attribute defaults to
None
, which indicates that a construct has not yet taken into account whether or not its appropriate for it to participate in caching; this is functionally equivalent to setting the value toFalse
, except that a warning is also emitted.This flag can be set to
True
on a particular class, if the SQL that corresponds to the object does not change based on attributes which are local to this class, and not its superclass.See also
Enabling Caching Support for Custom Constructs - General guideslines for setting the
HasCacheKey.inherit_cache
attribute for third-party or user defined SQL constructs.
-
method
sqlalchemy.sql.expression.ColumnElement.
is_(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.is_()
method ofColumnOperators
Implement the
IS
operator.Normally,
IS
is generated automatically when comparing to a value ofNone
, which resolves toNULL
. However, explicit usage ofIS
may be desirable if comparing to boolean values on certain platforms.See also
-
attribute
sqlalchemy.sql.expression.ColumnElement.
is_clause_element = True¶
-
method
sqlalchemy.sql.expression.ColumnElement.
is_distinct_from(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.is_distinct_from()
method ofColumnOperators
Implement the
IS DISTINCT FROM
operator.Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
is_dml = False¶
-
method
sqlalchemy.sql.expression.ColumnElement.
is_not(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.is_not()
method ofColumnOperators
Implement the
IS NOT
operator.Normally,
IS NOT
is generated automatically when comparing to a value ofNone
, which resolves toNULL
. However, explicit usage ofIS NOT
may be desirable if comparing to boolean values on certain platforms.Changed in version 1.4: The
is_not()
operator is renamed fromisnot()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
is_not_distinct_from(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.is_not_distinct_from()
method ofColumnOperators
Implement the
IS NOT DISTINCT FROM
operator.Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.
Changed in version 1.4: The
is_not_distinct_from()
operator is renamed fromisnot_distinct_from()
in previous releases. The previous name remains available for backwards compatibility.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
is_selectable = False¶
-
method
sqlalchemy.sql.expression.ColumnElement.
isnot(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.isnot()
method ofColumnOperators
Implement the
IS NOT
operator.Normally,
IS NOT
is generated automatically when comparing to a value ofNone
, which resolves toNULL
. However, explicit usage ofIS NOT
may be desirable if comparing to boolean values on certain platforms.Changed in version 1.4: The
is_not()
operator is renamed fromisnot()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
isnot_distinct_from(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.isnot_distinct_from()
method ofColumnOperators
Implement the
IS NOT DISTINCT FROM
operator.Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.
Changed in version 1.4: The
is_not_distinct_from()
operator is renamed fromisnot_distinct_from()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnElement.
istartswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ inherited from the
ColumnOperators.istartswith()
method ofColumnOperators
Implement the
istartswith
operator, e.g. case insensitive version ofColumnOperators.startswith()
.Produces a LIKE expression that tests against an insensitive match for the start of a string value:
lower(column) LIKE lower(<other>) || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.istartswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.istartswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.istartswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.istartswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.istartswith("foo%bar", autoescape=True)
Will render as:
lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.istartswith("foo/%bar", escape="^")
Will render as:
lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.istartswith.autoescape
:somecolumn.istartswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
See also
-
attribute
sqlalchemy.sql.expression.ColumnElement.
key: str | None = None¶ The ‘key’ that in some circumstances refers to this object in a Python namespace.
This typically refers to the “key” of the column as present in the
.c
collection of a selectable, e.g.sometable.c["somekey"]
would return aColumn
with a.key
of “somekey”.
-
method
sqlalchemy.sql.expression.ColumnElement.
label(name: str | None) → Label[_T]¶ Produce a column label, i.e.
<columnname> AS <name>
.This is a shortcut to the
label()
function.If ‘name’ is
None
, an anonymous label name will be generated.
-
method
sqlalchemy.sql.expression.ColumnElement.
like(other: Any, escape: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.like()
method ofColumnOperators
Implement the
like
operator.In a column context, produces the expression:
a LIKE other
E.g.:
stmt = select(sometable).\ where(sometable.c.column.like("%foobar%"))
- Parameters:
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
match(other: Any, **kwargs: Any) → ColumnOperators¶ inherited from the
ColumnOperators.match()
method ofColumnOperators
Implements a database-specific ‘match’ operator.
ColumnOperators.match()
attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:PostgreSQL - renders
x @@ plainto_tsquery(y)
Changed in version 2.0:
plainto_tsquery()
is used instead ofto_tsquery()
for PostgreSQL now; for compatibility with other forms, see Full Text Search.MySQL - renders
MATCH (x) AGAINST (y IN BOOLEAN MODE)
See also
match
- MySQL specific construct with additional features.Oracle - renders
CONTAINS(x, y)
other backends may provide special implementations.
Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQLite, for example.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
negation_clause: ColumnElement[bool]¶
-
method
sqlalchemy.sql.expression.ColumnElement.
not_ilike(other: Any, escape: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.not_ilike()
method ofColumnOperators
implement the
NOT ILIKE
operator.This is equivalent to using negation with
ColumnOperators.ilike()
, i.e.~x.ilike(y)
.Changed in version 1.4: The
not_ilike()
operator is renamed fromnotilike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
not_in(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.not_in()
method ofColumnOperators
implement the
NOT IN
operator.This is equivalent to using negation with
ColumnOperators.in_()
, i.e.~x.in_(y)
.In the case that
other
is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. Thecreate_engine.empty_in_strategy
may be used to alter this behavior.Changed in version 1.4: The
not_in()
operator is renamed fromnotin_()
in previous releases. The previous name remains available for backwards compatibility.Changed in version 1.2: The
ColumnOperators.in_()
andColumnOperators.not_in()
operators now produce a “static” expression for an empty IN sequence by default.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
not_like(other: Any, escape: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.not_like()
method ofColumnOperators
implement the
NOT LIKE
operator.This is equivalent to using negation with
ColumnOperators.like()
, i.e.~x.like(y)
.Changed in version 1.4: The
not_like()
operator is renamed fromnotlike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
notilike(other: Any, escape: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.notilike()
method ofColumnOperators
implement the
NOT ILIKE
operator.This is equivalent to using negation with
ColumnOperators.ilike()
, i.e.~x.ilike(y)
.Changed in version 1.4: The
not_ilike()
operator is renamed fromnotilike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
notin_(other: Any) → ColumnOperators¶ inherited from the
ColumnOperators.notin_()
method ofColumnOperators
implement the
NOT IN
operator.This is equivalent to using negation with
ColumnOperators.in_()
, i.e.~x.in_(y)
.In the case that
other
is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. Thecreate_engine.empty_in_strategy
may be used to alter this behavior.Changed in version 1.4: The
not_in()
operator is renamed fromnotin_()
in previous releases. The previous name remains available for backwards compatibility.Changed in version 1.2: The
ColumnOperators.in_()
andColumnOperators.not_in()
operators now produce a “static” expression for an empty IN sequence by default.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
notlike(other: Any, escape: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.notlike()
method ofColumnOperators
implement the
NOT LIKE
operator.This is equivalent to using negation with
ColumnOperators.like()
, i.e.~x.like(y)
.Changed in version 1.4: The
not_like()
operator is renamed fromnotlike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnElement.
nulls_first() → ColumnOperators¶ inherited from the
ColumnOperators.nulls_first()
method ofColumnOperators
Produce a
nulls_first()
clause against the parent object.Changed in version 1.4: The
nulls_first()
operator is renamed fromnullsfirst()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnElement.
nulls_last() → ColumnOperators¶ inherited from the
ColumnOperators.nulls_last()
method ofColumnOperators
Produce a
nulls_last()
clause against the parent object.Changed in version 1.4: The
nulls_last()
operator is renamed fromnullslast()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnElement.
nullsfirst() → ColumnOperators¶ inherited from the
ColumnOperators.nullsfirst()
method ofColumnOperators
Produce a
nulls_first()
clause against the parent object.Changed in version 1.4: The
nulls_first()
operator is renamed fromnullsfirst()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnElement.
nullslast() → ColumnOperators¶ inherited from the
ColumnOperators.nullslast()
method ofColumnOperators
Produce a
nulls_last()
clause against the parent object.Changed in version 1.4: The
nulls_last()
operator is renamed fromnullslast()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnElement.
op(opstring: str, precedence: int = 0, is_comparison: bool = False, return_type: Type[TypeEngine[Any]] | TypeEngine[Any] | None = None, python_impl: Callable[..., Any] | None = None) → Callable[[Any], Operators]¶ inherited from the
Operators.op()
method ofOperators
Produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in
somecolumn
.- Parameters:
opstring¶ – a string which will be output as the infix operator between this element and the expression passed to the generated function.
precedence¶ –
precedence which the database is expected to apply to the operator in SQL expressions. This integer value acts as a hint for the SQL compiler to know when explicit parenthesis should be rendered around a particular operation. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of
0
is lower than all operators except for the comma (,
) andAS
operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.See also
I’m using op() to generate a custom operator and my parenthesis are not coming out correctly - detailed description of how the SQLAlchemy SQL compiler renders parenthesis
is_comparison¶ –
legacy; if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like
==
,>
, etc. This flag is provided so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition.Using the
is_comparison
parameter is superseded by using theOperators.bool_op()
method instead; this more succinct operator sets this parameter automatically, but also provides correct PEP 484 typing support as the returned object will express a “boolean” datatype, i.e.BinaryExpression[bool]
.return_type¶ – a
TypeEngine
class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specifyOperators.op.is_comparison
will resolve toBoolean
, and those that do not will be of the same type as the left-hand operand.python_impl¶ –
an optional Python function that can evaluate two Python values in the same way as this operator works when run on the database server. Useful for in-Python SQL expression evaluation functions, such as for ORM hybrid attributes, and the ORM “evaluator” used to match objects in a session after a multi-row update or delete.
e.g.:
>>> expr = column('x').op('+', python_impl=lambda a, b: a + b)('y')
The operator for the above expression will also work for non-SQL left and right objects:
>>> expr.operator(5, 10) 15
New in version 2.0.
-
method
sqlalchemy.sql.expression.ColumnElement.
operate(op: OperatorType, *other: Any, **kwargs: Any) → ColumnElement[Any]¶ Operate on an argument.
This is the lowest level of operation, raises
NotImplementedError
by default.Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding
ColumnOperators
to applyfunc.lower()
to the left and right side:class MyComparator(ColumnOperators): def operate(self, op, other, **kwargs): return op(func.lower(self), func.lower(other), **kwargs)
- Parameters:
op¶ – Operator callable.
*other¶ – the ‘other’ side of the operation. Will be a single scalar for most operations.
**kwargs¶ – modifiers. These may be passed by special operators such as
ColumnOperators.contains()
.
-
method
sqlalchemy.sql.expression.ColumnElement.
params(_ClauseElement__optionaldict: Mapping[str, Any] | None = None, **kwargs: Any) → Self¶ inherited from the
ClauseElement.params()
method ofClauseElement
Return a copy with
bindparam()
elements replaced.Returns a copy of this ClauseElement with
bindparam()
elements replaced with values taken from the given dictionary:>>> clause = column('x') + bindparam('foo') >>> print(clause.compile().params) {'foo':None} >>> print(clause.params({'foo':7}).compile().params) {'foo':7}
-
attribute
sqlalchemy.sql.expression.ColumnElement.
primary_key: bool = False¶
-
attribute
sqlalchemy.sql.expression.ColumnElement.
proxy_set: util.generic_fn_descriptor[FrozenSet[Any]]¶ set of all columns we are proxying
as of 2.0 this is explicitly deannotated columns. previously it was effectively deannotated columns but wasn’t enforced. annotated columns should basically not go into sets if at all possible because their hashing behavior is very non-performant.
-
method
sqlalchemy.sql.expression.ColumnElement.
regexp_match(pattern: Any, flags: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.regexp_match()
method ofColumnOperators
Implements a database-specific ‘regexp match’ operator.
E.g.:
stmt = select(table.c.some_column).where( table.c.some_column.regexp_match('^(b|c)') )
ColumnOperators.regexp_match()
attempts to resolve to a REGEXP-like function or operator provided by the backend, however the specific regular expression syntax and flags available are not backend agnostic.Examples include:
PostgreSQL - renders
x ~ y
orx !~ y
when negated.Oracle - renders
REGEXP_LIKE(x, y)
SQLite - uses SQLite’s
REGEXP
placeholder operator and calls into the Pythonre.match()
builtin.other backends may provide special implementations.
Backends without any special implementation will emit the operator as “REGEXP” or “NOT REGEXP”. This is compatible with SQLite and MySQL, for example.
Regular expression support is currently implemented for Oracle, PostgreSQL, MySQL and MariaDB. Partial support is available for SQLite. Support among third-party dialects may vary.
- Parameters:
pattern¶ – The regular expression pattern string or column clause.
flags¶ – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern. When using the ignore case flag ‘i’ in PostgreSQL, the ignore case regexp match operator
~*
or!~*
will be used.
New in version 1.4.
Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
regexp_replace(pattern: Any, replacement: Any, flags: str | None = None) → ColumnOperators¶ inherited from the
ColumnOperators.regexp_replace()
method ofColumnOperators
Implements a database-specific ‘regexp replace’ operator.
E.g.:
stmt = select( table.c.some_column.regexp_replace( 'b(..)', 'XY', flags='g' ) )
ColumnOperators.regexp_replace()
attempts to resolve to a REGEXP_REPLACE-like function provided by the backend, that usually emit the functionREGEXP_REPLACE()
. However, the specific regular expression syntax and flags available are not backend agnostic.Regular expression replacement support is currently implemented for Oracle, PostgreSQL, MySQL 8 or greater and MariaDB. Support among third-party dialects may vary.
- Parameters:
pattern¶ – The regular expression pattern string or column clause.
pattern¶ – The replacement string or column clause.
flags¶ – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern.
New in version 1.4.
Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.
See also
-
method
sqlalchemy.sql.expression.ColumnElement.
reverse_operate(op: OperatorType, other: Any, **kwargs: Any) → ColumnElement[Any]¶ Reverse operate on an argument.
Usage is the same as
operate()
.
-
method
sqlalchemy.sql.expression.ColumnElement.
self_group(against: OperatorType | None = None) → ColumnElement[Any]¶ Apply a ‘grouping’ to this
ClauseElement
.This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by
select()
constructs when placed into the FROM clause of anotherselect()
. (Note that subqueries should be normally created using theSelect.alias()
method, as many platforms require nested SELECT statements to be named).As expressions are composed together, the application of
self_group()
is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression likex OR (y AND z)
- AND takes precedence over OR.The base
self_group()
method ofClauseElement
just returns self.
-
method
sqlalchemy.sql.expression.ColumnElement.
shares_lineage(othercolumn: ColumnElement[Any]) → bool¶ Return True if the given
ColumnElement
has a common ancestor to thisColumnElement
.
-
method
sqlalchemy.sql.expression.ColumnElement.
startswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ inherited from the
ColumnOperators.startswith()
method ofColumnOperators
Implement the
startswith
operator.Produces a LIKE expression that tests against a match for the start of a string value:
column LIKE <other> || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.startswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.startswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.startswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.startswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.startswith("foo%bar", autoescape=True)
Will render as:
somecolumn LIKE :param || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.startswith("foo/%bar", escape="^")
Will render as:
somecolumn LIKE :param || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.startswith.autoescape
:somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
stringify_dialect = 'default'¶
-
attribute
sqlalchemy.sql.expression.ColumnElement.
supports_execution = False¶
-
attribute
sqlalchemy.sql.expression.ColumnElement.
timetuple: Literal[None] = None¶ inherited from the
ColumnOperators.timetuple
attribute ofColumnOperators
Hack, allows datetime objects to be compared on the LHS.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
type: TypeEngine[_T]¶
-
method
sqlalchemy.sql.expression.ColumnElement.
unique_params(_ClauseElement__optionaldict: Dict[str, Any] | None = None, **kwargs: Any) → Self¶ inherited from the
ClauseElement.unique_params()
method ofClauseElement
Return a copy with
bindparam()
elements replaced.Same functionality as
ClauseElement.params()
, except adds unique=True to affected bind parameters so that multiple statements can be used.
-
attribute
sqlalchemy.sql.expression.ColumnElement.
uses_inspection = True¶
- sqlalchemy.sql.expression.ColumnExpressionArgument¶
General purpose “column expression” argument.
New in version 2.0.13.
This type is used for “column” kinds of expressions that typically represent a single SQL column expression, including
ColumnElement
, as well as ORM-mapped attributes that will have a__clause_element__()
method.
- class sqlalchemy.sql.expression.ColumnOperators¶
Defines boolean, comparison, and other operators for
ColumnElement
expressions.By default, all methods call down to
operate()
orreverse_operate()
, passing in the appropriate operator function from the Python builtinoperator
module or a SQLAlchemy-specific operator function fromsqlalchemy.expression.operators
. For example the__eq__
function:def __eq__(self, other): return self.operate(operators.eq, other)
Where
operators.eq
is essentially:def eq(a, b): return a == b
The core column expression unit
ColumnElement
overridesOperators.operate()
and others to return furtherColumnElement
constructs, so that the==
operation above is replaced by a clause construct.Members
__add__(), __and__(), __eq__(), __floordiv__(), __ge__(), __getitem__(), __gt__(), __hash__(), __invert__(), __le__(), __lshift__(), __lt__(), __mod__(), __mul__(), __ne__(), __neg__(), __or__(), __radd__(), __rfloordiv__(), __rmod__(), __rmul__(), __rshift__(), __rsub__(), __rtruediv__(), __sa_operate__(), __sub__(), __truediv__(), all_(), any_(), asc(), between(), bitwise_and(), bitwise_lshift(), bitwise_not(), bitwise_or(), bitwise_rshift(), bitwise_xor(), bool_op(), collate(), concat(), contains(), desc(), distinct(), endswith(), icontains(), iendswith(), ilike(), in_(), is_(), is_distinct_from(), is_not(), is_not_distinct_from(), isnot(), isnot_distinct_from(), istartswith(), like(), match(), not_ilike(), not_in(), not_like(), notilike(), notin_(), notlike(), nulls_first(), nulls_last(), nullsfirst(), nullslast(), op(), operate(), regexp_match(), regexp_replace(), reverse_operate(), startswith(), timetuple
Class signature
class
sqlalchemy.sql.expression.ColumnOperators
(sqlalchemy.sql.expression.Operators
)-
method
sqlalchemy.sql.expression.ColumnOperators.
__add__(other: Any) → ColumnOperators¶ Implement the
+
operator.In a column context, produces the clause
a + b
if the parent object has non-string affinity. If the parent object has a string affinity, produces the concatenation operator,a || b
- seeColumnOperators.concat()
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__and__(other: Any) → Operators¶ inherited from the
sqlalchemy.sql.expression.Operators.__and__
method ofOperators
Implement the
&
operator.When used with SQL expressions, results in an AND operation, equivalent to
and_()
, that is:a & b
is equivalent to:
from sqlalchemy import and_ and_(a, b)
Care should be taken when using
&
regarding operator precedence; the&
operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:(a == 2) & (b == 4)
-
method
sqlalchemy.sql.expression.ColumnOperators.
__eq__(other: Any) → ColumnOperators¶ Implement the
==
operator.In a column context, produces the clause
a = b
. If the target isNone
, producesa IS NULL
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__floordiv__(other: Any) → ColumnOperators¶ Implement the
//
operator.In a column context, produces the clause
a / b
, which is the same as “truediv”, but considers the result type to be integer.New in version 2.0.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__ge__(other: Any) → ColumnOperators¶ Implement the
>=
operator.In a column context, produces the clause
a >= b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__getitem__(index: Any) → ColumnOperators¶ Implement the [] operator.
This can be used by some database-specific types such as PostgreSQL ARRAY and HSTORE.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__gt__(other: Any) → ColumnOperators¶ Implement the
>
operator.In a column context, produces the clause
a > b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__hash__()¶ Return hash(self).
-
method
sqlalchemy.sql.expression.ColumnOperators.
__invert__() → Operators¶ inherited from the
sqlalchemy.sql.expression.Operators.__invert__
method ofOperators
Implement the
~
operator.When used with SQL expressions, results in a NOT operation, equivalent to
not_()
, that is:~a
is equivalent to:
from sqlalchemy import not_ not_(a)
-
method
sqlalchemy.sql.expression.ColumnOperators.
__le__(other: Any) → ColumnOperators¶ Implement the
<=
operator.In a column context, produces the clause
a <= b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__lshift__(other: Any) → ColumnOperators¶ implement the << operator.
Not used by SQLAlchemy core, this is provided for custom operator systems which want to use << as an extension point.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__lt__(other: Any) → ColumnOperators¶ Implement the
<
operator.In a column context, produces the clause
a < b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__mod__(other: Any) → ColumnOperators¶ Implement the
%
operator.In a column context, produces the clause
a % b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__mul__(other: Any) → ColumnOperators¶ Implement the
*
operator.In a column context, produces the clause
a * b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__ne__(other: Any) → ColumnOperators¶ Implement the
!=
operator.In a column context, produces the clause
a != b
. If the target isNone
, producesa IS NOT NULL
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__neg__() → ColumnOperators¶ Implement the
-
operator.In a column context, produces the clause
-a
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__or__(other: Any) → Operators¶ inherited from the
sqlalchemy.sql.expression.Operators.__or__
method ofOperators
Implement the
|
operator.When used with SQL expressions, results in an OR operation, equivalent to
or_()
, that is:a | b
is equivalent to:
from sqlalchemy import or_ or_(a, b)
Care should be taken when using
|
regarding operator precedence; the|
operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:(a == 2) | (b == 4)
-
method
sqlalchemy.sql.expression.ColumnOperators.
__radd__(other: Any) → ColumnOperators¶ Implement the
+
operator in reverse.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__rfloordiv__(other: Any) → ColumnOperators¶ Implement the
//
operator in reverse.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__rmod__(other: Any) → ColumnOperators¶ Implement the
%
operator in reverse.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__rmul__(other: Any) → ColumnOperators¶ Implement the
*
operator in reverse.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__rshift__(other: Any) → ColumnOperators¶ implement the >> operator.
Not used by SQLAlchemy core, this is provided for custom operator systems which want to use >> as an extension point.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__rsub__(other: Any) → ColumnOperators¶ Implement the
-
operator in reverse.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__rtruediv__(other: Any) → ColumnOperators¶ Implement the
/
operator in reverse.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__sa_operate__(op: OperatorType, *other: Any, **kwargs: Any) → Operators¶ inherited from the
sqlalchemy.sql.expression.Operators.__sa_operate__
method ofOperators
Operate on an argument.
This is the lowest level of operation, raises
NotImplementedError
by default.Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding
ColumnOperators
to applyfunc.lower()
to the left and right side:class MyComparator(ColumnOperators): def operate(self, op, other, **kwargs): return op(func.lower(self), func.lower(other), **kwargs)
- Parameters:
op¶ – Operator callable.
*other¶ – the ‘other’ side of the operation. Will be a single scalar for most operations.
**kwargs¶ – modifiers. These may be passed by special operators such as
ColumnOperators.contains()
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__sub__(other: Any) → ColumnOperators¶ Implement the
-
operator.In a column context, produces the clause
a - b
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
__truediv__(other: Any) → ColumnOperators¶ Implement the
/
operator.In a column context, produces the clause
a / b
, and considers the result type to be numeric.Changed in version 2.0: The truediv operator against two integers is now considered to return a numeric value. Behavior on specific backends may vary.
-
method
sqlalchemy.sql.expression.ColumnOperators.
all_() → ColumnOperators¶ Produce an
all_()
clause against the parent object.See the documentation for
all_()
for examples.Note
be sure to not confuse the newer
ColumnOperators.all_()
method with the legacy version of this method, theComparator.all()
method that’s specific toARRAY
, which uses a different calling style.
-
method
sqlalchemy.sql.expression.ColumnOperators.
any_() → ColumnOperators¶ Produce an
any_()
clause against the parent object.See the documentation for
any_()
for examples.Note
be sure to not confuse the newer
ColumnOperators.any_()
method with the legacy version of this method, theComparator.any()
method that’s specific toARRAY
, which uses a different calling style.
-
method
sqlalchemy.sql.expression.ColumnOperators.
asc() → ColumnOperators¶ Produce a
asc()
clause against the parent object.
-
method
sqlalchemy.sql.expression.ColumnOperators.
between(cleft: Any, cright: Any, symmetric: bool = False) → ColumnOperators¶ Produce a
between()
clause against the parent object, given the lower and upper range.
-
method
sqlalchemy.sql.expression.ColumnOperators.
bitwise_and(other: Any) → ColumnOperators¶ Produce a bitwise AND operation, typically via the
&
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
bitwise_lshift(other: Any) → ColumnOperators¶ Produce a bitwise LSHIFT operation, typically via the
<<
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
bitwise_not() → ColumnOperators¶ Produce a bitwise NOT operation, typically via the
~
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
bitwise_or(other: Any) → ColumnOperators¶ Produce a bitwise OR operation, typically via the
|
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
bitwise_rshift(other: Any) → ColumnOperators¶ Produce a bitwise RSHIFT operation, typically via the
>>
operator.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
bitwise_xor(other: Any) → ColumnOperators¶ Produce a bitwise XOR operation, typically via the
^
operator, or#
for PostgreSQL.New in version 2.0.2.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
bool_op(opstring: str, precedence: int = 0, python_impl: Callable[[...], Any] | None = None) → Callable[[Any], Operators]¶ inherited from the
Operators.bool_op()
method ofOperators
Return a custom boolean operator.
This method is shorthand for calling
Operators.op()
and passing theOperators.op.is_comparison
flag with True. A key advantage to usingOperators.bool_op()
is that when using column constructs, the “boolean” nature of the returned expression will be present for PEP 484 purposes.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
collate(collation: str) → ColumnOperators¶ Produce a
collate()
clause against the parent object, given the collation string.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
concat(other: Any) → ColumnOperators¶ Implement the ‘concat’ operator.
In a column context, produces the clause
a || b
, or uses theconcat()
operator on MySQL.
-
method
sqlalchemy.sql.expression.ColumnOperators.
contains(other: Any, **kw: Any) → ColumnOperators¶ Implement the ‘contains’ operator.
Produces a LIKE expression that tests against a match for the middle of a string value:
column LIKE '%' || <other> || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.contains("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.contains.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.contains.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.contains.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.contains("foo%bar", autoescape=True)
Will render as:
somecolumn LIKE '%' || :param || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.contains("foo/%bar", escape="^")
Will render as:
somecolumn LIKE '%' || :param || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.contains.autoescape
:somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
-
method
sqlalchemy.sql.expression.ColumnOperators.
desc() → ColumnOperators¶ Produce a
desc()
clause against the parent object.
-
method
sqlalchemy.sql.expression.ColumnOperators.
distinct() → ColumnOperators¶ Produce a
distinct()
clause against the parent object.
-
method
sqlalchemy.sql.expression.ColumnOperators.
endswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ Implement the ‘endswith’ operator.
Produces a LIKE expression that tests against a match for the end of a string value:
column LIKE '%' || <other>
E.g.:
stmt = select(sometable).\ where(sometable.c.column.endswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.endswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.endswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.endswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.endswith("foo%bar", autoescape=True)
Will render as:
somecolumn LIKE '%' || :param ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.endswith("foo/%bar", escape="^")
Will render as:
somecolumn LIKE '%' || :param ESCAPE '^'
The parameter may also be combined with
ColumnOperators.endswith.autoescape
:somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
-
method
sqlalchemy.sql.expression.ColumnOperators.
icontains(other: Any, **kw: Any) → ColumnOperators¶ Implement the
icontains
operator, e.g. case insensitive version ofColumnOperators.contains()
.Produces a LIKE expression that tests against an insensitive match for the middle of a string value:
lower(column) LIKE '%' || lower(<other>) || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.icontains("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.icontains.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.icontains.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.icontains.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.icontains("foo%bar", autoescape=True)
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.icontains("foo/%bar", escape="^")
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.contains.autoescape
:somecolumn.icontains("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
iendswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ Implement the
iendswith
operator, e.g. case insensitive version ofColumnOperators.endswith()
.Produces a LIKE expression that tests against an insensitive match for the end of a string value:
lower(column) LIKE '%' || lower(<other>)
E.g.:
stmt = select(sometable).\ where(sometable.c.column.iendswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.iendswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.iendswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.iendswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.iendswith("foo%bar", autoescape=True)
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.iendswith("foo/%bar", escape="^")
Will render as:
lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '^'
The parameter may also be combined with
ColumnOperators.iendswith.autoescape
:somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
ilike(other: Any, escape: str | None = None) → ColumnOperators¶ Implement the
ilike
operator, e.g. case insensitive LIKE.In a column context, produces an expression either of the form:
lower(a) LIKE lower(other)
Or on backends that support the ILIKE operator:
a ILIKE other
E.g.:
stmt = select(sometable).\ where(sometable.c.column.ilike("%foobar%"))
- Parameters:
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
in_(other: Any) → ColumnOperators¶ Implement the
in
operator.In a column context, produces the clause
column IN <other>
.The given parameter
other
may be:A list of literal values, e.g.:
stmt.where(column.in_([1, 2, 3]))
In this calling form, the list of items is converted to a set of bound parameters the same length as the list given:
WHERE COL IN (?, ?, ?)
A list of tuples may be provided if the comparison is against a
tuple_()
containing multiple expressions:from sqlalchemy import tuple_ stmt.where(tuple_(col1, col2).in_([(1, 10), (2, 20), (3, 30)]))
An empty list, e.g.:
stmt.where(column.in_([]))
In this calling form, the expression renders an “empty set” expression. These expressions are tailored to individual backends and are generally trying to get an empty SELECT statement as a subquery. Such as on SQLite, the expression is:
WHERE col IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)
Changed in version 1.4: empty IN expressions now use an execution-time generated SELECT subquery in all cases.
A bound parameter, e.g.
bindparam()
, may be used if it includes thebindparam.expanding
flag:stmt.where(column.in_(bindparam('value', expanding=True)))
In this calling form, the expression renders a special non-SQL placeholder expression that looks like:
WHERE COL IN ([EXPANDING_value])
This placeholder expression is intercepted at statement execution time to be converted into the variable number of bound parameter form illustrated earlier. If the statement were executed as:
connection.execute(stmt, {"value": [1, 2, 3]})
The database would be passed a bound parameter for each value:
WHERE COL IN (?, ?, ?)
New in version 1.2: added “expanding” bound parameters
If an empty list is passed, a special “empty list” expression, which is specific to the database in use, is rendered. On SQLite this would be:
WHERE COL IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)
New in version 1.3: “expanding” bound parameters now support empty lists
a
select()
construct, which is usually a correlated scalar select:stmt.where( column.in_( select(othertable.c.y). where(table.c.x == othertable.c.x) ) )
In this calling form,
ColumnOperators.in_()
renders as given:WHERE COL IN (SELECT othertable.y FROM othertable WHERE othertable.x = table.x)
- Parameters:
other¶ – a list of literals, a
select()
construct, or abindparam()
construct that includes thebindparam.expanding
flag set to True.
-
method
sqlalchemy.sql.expression.ColumnOperators.
is_(other: Any) → ColumnOperators¶ Implement the
IS
operator.Normally,
IS
is generated automatically when comparing to a value ofNone
, which resolves toNULL
. However, explicit usage ofIS
may be desirable if comparing to boolean values on certain platforms.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
is_distinct_from(other: Any) → ColumnOperators¶ Implement the
IS DISTINCT FROM
operator.Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.
-
method
sqlalchemy.sql.expression.ColumnOperators.
is_not(other: Any) → ColumnOperators¶ Implement the
IS NOT
operator.Normally,
IS NOT
is generated automatically when comparing to a value ofNone
, which resolves toNULL
. However, explicit usage ofIS NOT
may be desirable if comparing to boolean values on certain platforms.Changed in version 1.4: The
is_not()
operator is renamed fromisnot()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
is_not_distinct_from(other: Any) → ColumnOperators¶ Implement the
IS NOT DISTINCT FROM
operator.Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.
Changed in version 1.4: The
is_not_distinct_from()
operator is renamed fromisnot_distinct_from()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnOperators.
isnot(other: Any) → ColumnOperators¶ Implement the
IS NOT
operator.Normally,
IS NOT
is generated automatically when comparing to a value ofNone
, which resolves toNULL
. However, explicit usage ofIS NOT
may be desirable if comparing to boolean values on certain platforms.Changed in version 1.4: The
is_not()
operator is renamed fromisnot()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
isnot_distinct_from(other: Any) → ColumnOperators¶ Implement the
IS NOT DISTINCT FROM
operator.Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.
Changed in version 1.4: The
is_not_distinct_from()
operator is renamed fromisnot_distinct_from()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnOperators.
istartswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators¶ Implement the
istartswith
operator, e.g. case insensitive version ofColumnOperators.startswith()
.Produces a LIKE expression that tests against an insensitive match for the start of a string value:
lower(column) LIKE lower(<other>) || '%'
E.g.:
stmt = select(sometable).\ where(sometable.c.column.istartswith("foobar"))
Since the operator uses
LIKE
, wildcard characters"%"
and"_"
that are present inside the <other> expression will behave like wildcards as well. For literal string values, theColumnOperators.istartswith.autoescape
flag may be set toTrue
to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, theColumnOperators.istartswith.escape
parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.- Parameters:
other¶ – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters
%
and_
are not escaped by default unless theColumnOperators.istartswith.autoescape
flag is set to True.autoescape¶ –
boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of
"%"
,"_"
and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.An expression such as:
somecolumn.istartswith("foo%bar", autoescape=True)
Will render as:
lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '/'
With the value of
:param
as"foo/%bar"
.escape¶ –
a character which when given will render with the
ESCAPE
keyword to establish that character as the escape character. This character can then be placed preceding occurrences of%
and_
to allow them to act as themselves and not wildcard characters.An expression such as:
somecolumn.istartswith("foo/%bar", escape="^")
Will render as:
lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '^'
The parameter may also be combined with
ColumnOperators.istartswith.autoescape
:somecolumn.istartswith("foo%bar^bat", escape="^", autoescape=True)
Where above, the given literal parameter will be converted to
"foo^%bar^^bat"
before being passed to the database.
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
like(other: Any, escape: str | None = None) → ColumnOperators¶ Implement the
like
operator.In a column context, produces the expression:
a LIKE other
E.g.:
stmt = select(sometable).\ where(sometable.c.column.like("%foobar%"))
- Parameters:
See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
match(other: Any, **kwargs: Any) → ColumnOperators¶ Implements a database-specific ‘match’ operator.
ColumnOperators.match()
attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:PostgreSQL - renders
x @@ plainto_tsquery(y)
Changed in version 2.0:
plainto_tsquery()
is used instead ofto_tsquery()
for PostgreSQL now; for compatibility with other forms, see Full Text Search.MySQL - renders
MATCH (x) AGAINST (y IN BOOLEAN MODE)
See also
match
- MySQL specific construct with additional features.Oracle - renders
CONTAINS(x, y)
other backends may provide special implementations.
Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQLite, for example.
-
method
sqlalchemy.sql.expression.ColumnOperators.
not_ilike(other: Any, escape: str | None = None) → ColumnOperators¶ implement the
NOT ILIKE
operator.This is equivalent to using negation with
ColumnOperators.ilike()
, i.e.~x.ilike(y)
.Changed in version 1.4: The
not_ilike()
operator is renamed fromnotilike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
not_in(other: Any) → ColumnOperators¶ implement the
NOT IN
operator.This is equivalent to using negation with
ColumnOperators.in_()
, i.e.~x.in_(y)
.In the case that
other
is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. Thecreate_engine.empty_in_strategy
may be used to alter this behavior.Changed in version 1.4: The
not_in()
operator is renamed fromnotin_()
in previous releases. The previous name remains available for backwards compatibility.Changed in version 1.2: The
ColumnOperators.in_()
andColumnOperators.not_in()
operators now produce a “static” expression for an empty IN sequence by default.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
not_like(other: Any, escape: str | None = None) → ColumnOperators¶ implement the
NOT LIKE
operator.This is equivalent to using negation with
ColumnOperators.like()
, i.e.~x.like(y)
.Changed in version 1.4: The
not_like()
operator is renamed fromnotlike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
notilike(other: Any, escape: str | None = None) → ColumnOperators¶ implement the
NOT ILIKE
operator.This is equivalent to using negation with
ColumnOperators.ilike()
, i.e.~x.ilike(y)
.Changed in version 1.4: The
not_ilike()
operator is renamed fromnotilike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
notin_(other: Any) → ColumnOperators¶ implement the
NOT IN
operator.This is equivalent to using negation with
ColumnOperators.in_()
, i.e.~x.in_(y)
.In the case that
other
is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. Thecreate_engine.empty_in_strategy
may be used to alter this behavior.Changed in version 1.4: The
not_in()
operator is renamed fromnotin_()
in previous releases. The previous name remains available for backwards compatibility.Changed in version 1.2: The
ColumnOperators.in_()
andColumnOperators.not_in()
operators now produce a “static” expression for an empty IN sequence by default.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
notlike(other: Any, escape: str | None = None) → ColumnOperators¶ implement the
NOT LIKE
operator.This is equivalent to using negation with
ColumnOperators.like()
, i.e.~x.like(y)
.Changed in version 1.4: The
not_like()
operator is renamed fromnotlike()
in previous releases. The previous name remains available for backwards compatibility.See also
-
method
sqlalchemy.sql.expression.ColumnOperators.
nulls_first() → ColumnOperators¶ Produce a
nulls_first()
clause against the parent object.Changed in version 1.4: The
nulls_first()
operator is renamed fromnullsfirst()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnOperators.
nulls_last() → ColumnOperators¶ Produce a
nulls_last()
clause against the parent object.Changed in version 1.4: The
nulls_last()
operator is renamed fromnullslast()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnOperators.
nullsfirst() → ColumnOperators¶ Produce a
nulls_first()
clause against the parent object.Changed in version 1.4: The
nulls_first()
operator is renamed fromnullsfirst()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnOperators.
nullslast() → ColumnOperators¶ Produce a
nulls_last()
clause against the parent object.Changed in version 1.4: The
nulls_last()
operator is renamed fromnullslast()
in previous releases. The previous name remains available for backwards compatibility.
-
method
sqlalchemy.sql.expression.ColumnOperators.
op(opstring: str, precedence: int = 0, is_comparison: bool = False, return_type: Type[TypeEngine[Any]] | TypeEngine[Any] | None = None, python_impl: Callable[..., Any] | None = None) → Callable[[Any], Operators]¶ inherited from the
Operators.op()
method ofOperators
Produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in
somecolumn
.- Parameters:
opstring¶ – a string which will be output as the infix operator between this element and the expression passed to the generated function.
precedence¶ –
precedence which the database is expected to apply to the operator in SQL expressions. This integer value acts as a hint for the SQL compiler to know when explicit parenthesis should be rendered around a particular operation. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of
0
is lower than all operators except for the comma (,
) andAS
operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.See also
I’m using op() to generate a custom operator and my parenthesis are not coming out correctly - detailed description of how the SQLAlchemy SQL compiler renders parenthesis
is_comparison¶ –
legacy; if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like
==
,>
, etc. This flag is provided so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition.Using the
is_comparison
parameter is superseded by using theOperators.bool_op()
method instead; this more succinct operator sets this parameter automatically, but also provides correct PEP 484 typing support as the returned object will express a “boolean” datatype, i.e.BinaryExpression[bool]
.return_type¶ – a
TypeEngine
class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specifyOperators.op.is_comparison
will resolve toBoolean
, and those that do not will be of the same type as the left-hand operand.python_impl¶ –
an optional Python function that can evaluate two Python values in the same way as this operator works when run on the database server. Useful for in-Python SQL expression evaluation functions, such as for ORM hybrid attributes, and the ORM “evaluator” used to match objects in a session after a multi-row update or delete.
e.g.:
>>> expr = column('x').op('+', python_impl=lambda a, b: a + b)('y')
The operator for the above expression will also work for non-SQL left and right objects:
>>> expr.operator(5, 10) 15
New in version 2.0.
-
method
sqlalchemy.sql.expression.ColumnOperators.
operate(op: OperatorType, *other: Any, **kwargs: Any) → Operators¶ inherited from the
Operators.operate()
method ofOperators
Operate on an argument.
This is the lowest level of operation, raises
NotImplementedError
by default.Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding
ColumnOperators
to applyfunc.lower()
to the left and right side:class MyComparator(ColumnOperators): def operate(self, op, other, **kwargs): return op(func.lower(self), func.lower(other), **kwargs)
- Parameters:
op¶ – Operator callable.
*other¶ – the ‘other’ side of the operation. Will be a single scalar for most operations.
**kwargs¶ – modifiers. These may be passed by special operators such as
ColumnOperators.contains()
.
-
method
sqlalchemy.sql.expression.ColumnOperators.
regexp_match(pattern: Any, flags: str | None = None) → ColumnOperators¶ Implements a database-specific ‘regexp match’ operator.
E.g.:
stmt = select(table.c.some_column).where( table.c.some_column.regexp_match('^(b|c)') )
ColumnOperators.regexp_match()
attempts to resolve to a REGEXP-like function or operator provided by the backend, however the specific regular expression syntax and flags available are not backend agnostic.Examples include:
PostgreSQL - renders
x ~ y
orx !~ y
when negated.Oracle - renders
-
method