SQL and Generic Functions
SQL functions which are known to SQLAlchemy with regards to database-specific rendering, return types and argument behavior. Generic functions are invoked like all SQL functions, using the func
attribute:
select(func.count()).select_from(sometable)
Note that any name not known to func
generates the function name as is - there is no restriction on what SQL functions can be called, known or unknown to SQLAlchemy, built-in or user defined. The section here only describes those functions where SQLAlchemy already knows what argument and return types are in use.
See also
Working with SQL Functions - in the SQLAlchemy 1.4 / 2.0 Tutorial
SQL function API, factories, and built-in functions.
Object Name | Description |
---|---|
Define a function in “ansi” format, which doesn’t render parenthesis. | |
Support for the ARRAY_AGG function. | |
The CHAR_LENGTH() SQL function. | |
The SQL CONCAT() function, which concatenates strings. | |
The ANSI COUNT aggregate function. With no arguments, emits COUNT *. | |
Implement the | |
Implement the | |
The CURRENT_DATE() SQL function. | |
The CURRENT_TIME() SQL function. | |
The CURRENT_TIMESTAMP() SQL function. | |
The CURRENT_USER() SQL function. | |
Implement the | |
Describe a named SQL function. | |
Base for SQL function-oriented constructs. | |
Define a ‘generic’ function. | |
Implement the | |
The localtime() SQL function. | |
The localtimestamp() SQL function. | |
The SQL MAX() aggregate function. | |
The SQL MIN() aggregate function. | |
Implement the | |
Represent the ‘next value’, given a | |
The SQL now() datetime function. | |
Define a function where the return type is based on the sort expression type as defined by the expression passed to the | |
Implement the | |
Implement the | |
Implement the | |
The RANDOM() SQL function. | |
Implement the | |
| Associate a callable with a particular func. name. |
Define a function whose return type is the same as its arguments. | |
Implement the | |
The SESSION_USER() SQL function. | |
The SQL SUM() aggregate function. | |
The SYSDATE() SQL function. | |
The USER() SQL function. |
class sqlalchemy.sql.functions.``AnsiFunction
(\args, **kwargs*)
Define a function in “ansi” format, which doesn’t render parenthesis.
Class signature
class sqlalchemy.sql.functions.AnsiFunction
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``Function
(name, \clauses, **kw*)
Describe a named SQL function.
The Function
object is typically generated from the func
generation object.
Parameters
*clauses – list of column expressions that form the arguments of the SQL function call.
type_ – optional
TypeEngine
datatype object that will be used as the return value of the column expression generated by this function call.packagenames –
a string which indicates package prefix names to be prepended to the function name when the SQL is generated. The
func
generator creates these when it is called using dotted format, e.g.:func.mypackage.some_function(col1, col2)
See also
Working with SQL Functions - in the SQLAlchemy 1.4 / 2.0 Tutorial
func
- namespace which produces registered or ad-hoc Function
instances.
GenericFunction
- allows creation of registered function types.
Class signature
class sqlalchemy.sql.functions.Function
(sqlalchemy.sql.functions.FunctionElement
)
method
sqlalchemy.sql.functions.Function.
__init__
(name, \clauses, **kw*)Construct a
Function
.The
func
construct is normally used to construct newFunction
instances.attribute
sqlalchemy.sql.functions.Function.
type
= NullType()A
TypeEngine
object which refers to the SQL return type represented by this SQL function.This datatype may be configured when generating a
Function
object by passing theFunction.type_
parameter, e.g.:>>> select(func.lower("some VALUE", type_=String))
The small number of built-in classes of
Function
come with a built-in datatype that’s appropriate to the class of function and its arguments. For functions that aren’t known, the type defaults to the “null type”.
class sqlalchemy.sql.functions.``FunctionAsBinary
(fn, left_index, right_index)
Class signature
class sqlalchemy.sql.functions.FunctionAsBinary
(sqlalchemy.sql.expression.BinaryExpression
)
class sqlalchemy.sql.functions.``FunctionElement
(\clauses, **kwargs*)
Base for SQL function-oriented constructs.
See also
Functions - in the Core tutorial
Function
- named SQL function.
func
- namespace which produces registered or ad-hoc Function
instances.
GenericFunction
- allows creation of registered function types.
Class signature
class sqlalchemy.sql.functions.FunctionElement
(sqlalchemy.sql.expression.Executable
, sqlalchemy.sql.expression.ColumnElement
, sqlalchemy.sql.expression.FromClause
, sqlalchemy.sql.expression.Generative
)
method
sqlalchemy.sql.functions.FunctionElement.
__init__
(\clauses, **kwargs*)Construct a
FunctionElement
.Parameters
*clauses – list of column expressions that form the arguments of the SQL function call.
**kwargs – additional kwargs are typically consumed by subclasses.
See also
[`func`]($f62ce11674ae62ed.md#sqlalchemy.sql.expression.func "sqlalchemy.sql.expression.func")
[`Function`](#sqlalchemy.sql.functions.Function "sqlalchemy.sql.functions.Function")
method
sqlalchemy.sql.functions.FunctionElement.
alias
(name=None)Produce a
Alias
construct against thisFunctionElement
.Tip
The
FunctionElement.alias()
method is part of the mechanism by which “table valued” SQL functions are created. However, most use cases are covered by higher level methods onFunctionElement
includingFunctionElement.table_valued()
, andFunctionElement.column_valued()
.This construct wraps the function in a named alias which is suitable for the FROM clause, in the style accepted for example by PostgreSQL. A column expression is also provided using the special
.column
attribute, which may be used to refer to the output of the function as a scalar value in the columns or where clause, for a backend such as PostgreSQL.For a full table-valued expression, use the
FunctionElement.table_valued()
method first to establish named columns.e.g.:
>>> from sqlalchemy import func, select, column
>>> data_view = func.unnest([1, 2, 3]).alias("data_view")
>>> print(select(data_view.column))
SELECT data_view
FROM unnest(:unnest_1) AS data_view
The
FunctionElement.column_valued()
method provides a shortcut for the above pattern:>>> data_view = func.unnest([1, 2, 3]).column_valued("data_view")
>>> print(select(data_view))
SELECT data_view
FROM unnest(:unnest_1) AS data_view
New in version 1.4.0b2: Added the
.column
accessorSee also
Table-Valued Functions - in the SQLAlchemy 1.4 / 2.0 Tutorial
FunctionElement.table_valued()
method
sqlalchemy.sql.functions.FunctionElement.
as_comparison
(left_index, right_index)Interpret this expression as a boolean comparison between two values.
This method is used for an ORM use case described at Custom operators based on SQL functions.
A hypothetical SQL function “is_equal()” which compares to values for equality would be written in the Core expression language as:
expr = func.is_equal("a", "b")
If “is_equal()” above is comparing “a” and “b” for equality, the
FunctionElement.as_comparison()
method would be invoked as:expr = func.is_equal("a", "b").as_comparison(1, 2)
Where above, the integer value “1” refers to the first argument of the “is_equal()” function and the integer value “2” refers to the second.
This would create a
BinaryExpression
that is equivalent to:BinaryExpression("a", "b", operator=op.eq)
However, at the SQL level it would still render as “is_equal(‘a’, ‘b’)”.
The ORM, when it loads a related object or collection, needs to be able to manipulate the “left” and “right” sides of the ON clause of a JOIN expression. The purpose of this method is to provide a SQL function construct that can also supply this information to the ORM, when used with the
relationship.primaryjoin
parameter. The return value is a containment object calledFunctionAsBinary
.An ORM example is as follows:
class Venue(Base):
__tablename__ = 'venue'
id = Column(Integer, primary_key=True)
name = Column(String)
descendants = relationship(
"Venue",
primaryjoin=func.instr(
remote(foreign(name)), name + "/"
).as_comparison(1, 2) == 1,
viewonly=True,
order_by=name
)
Above, the “Venue” class can load descendant “Venue” objects by determining if the name of the parent Venue is contained within the start of the hypothetical descendant value’s name, e.g. “parent1” would match up to “parent1/child1”, but not to “parent2/child1”.
Possible use cases include the “materialized path” example given above, as well as making use of special SQL functions such as geometric functions to create join conditions.
Parameters
left_index – the integer 1-based index of the function argument that serves as the “left” side of the expression.
right_index – the integer 1-based index of the function argument that serves as the “right” side of the expression.
New in version 1.3.
See also
[Custom operators based on SQL functions]($e1f42b7742e49253.md#relationship-custom-operator-sql-function) - example use within the ORM
attribute
sqlalchemy.sql.functions.FunctionElement.
clauses
Return the underlying
ClauseList
which contains the arguments for thisFunctionElement
.method
sqlalchemy.sql.functions.FunctionElement.
column_valued
(name=None)Return this
FunctionElement
as a column expression that selects from itself as a FROM clause.E.g.:
>>> from sqlalchemy import select, func
>>> gs = func.generate_series(1, 5, -1).column_valued()
>>> print(select(gs))
SELECT anon_1
FROM generate_series(:generate_series_1, :generate_series_2, :generate_series_3) AS anon_1
This is shorthand for:
gs = func.generate_series(1, 5, -1).alias().column
See also
Column Valued Functions - Table Valued Function as a Scalar Column - in the SQLAlchemy 1.4 / 2.0 Tutorial
Column Valued Functions - in the PostgreSQL documentation
attribute
sqlalchemy.sql.functions.FunctionElement.
columns
The set of columns exported by this
FunctionElement
.This is a placeholder collection that allows the function to be placed in the FROM clause of a statement:
>>> from sqlalchemy import column, select, func
>>> stmt = select(column('x'), column('y')).select_from(func.myfunction())
>>> print(stmt)
SELECT x, y FROM myfunction()
The above form is a legacy feature that is now superseded by the fully capable
FunctionElement.table_valued()
method; see that method for details.See also
FunctionElement.table_valued()
- generates table-valued SQL function expressions.method
sqlalchemy.sql.functions.FunctionElement.
execute
()Execute this
FunctionElement
against an embedded ‘bind’.Deprecated since version 1.4: The
FunctionElement.execute()
method is considered legacy as of the 1.x series of SQLAlchemy and will be removed in 2.0. All statement execution in SQLAlchemy 2.0 is performed by theConnection.execute()
method ofConnection
, or in the ORM by theSession.execute()
method ofSession
. (Background on SQLAlchemy 2.0 at: Migrating to SQLAlchemy 2.0)This first calls
FunctionElement.select()
to produce a SELECT construct.Note that
FunctionElement
can be passed to theConnectable.execute()
method ofConnection
orEngine
.method
sqlalchemy.sql.functions.FunctionElement.
filter
(\criterion*)Produce a FILTER clause against this function.
Used against aggregate and window functions, for database backends that support the “FILTER” clause.
The expression:
func.count(1).filter(True)
is shorthand for:
from sqlalchemy import funcfilter
funcfilter(func.count(1), True)
New in version 1.0.0.
See also
Special Modifiers WITHIN GROUP, FILTER - in the SQLAlchemy 1.4 / 2.0 Tutorial
method
sqlalchemy.sql.functions.FunctionElement.
over
(partition_by=None, order_by=None, rows=None, range_=None)Produce an OVER clause against this function.
Used against aggregate or so-called “window” functions, for database backends that support window functions.
The expression:
func.row_number().over(order_by='x')
is shorthand for:
from sqlalchemy import over
over(func.row_number(), order_by='x')
See
over()
for a full description.See also
Using Window Functions - in the SQLAlchemy 1.4 / 2.0 Tutorial
method
sqlalchemy.sql.functions.FunctionElement.
scalar
()Execute this
FunctionElement
against an embedded ‘bind’ and return a scalar value.Deprecated since version 1.4: The
FunctionElement.scalar()
method is considered legacy as of the 1.x series of SQLAlchemy and will be removed in 2.0. Scalar execution in SQLAlchemy 2.0 is performed by theConnection.scalar()
method ofConnection
, or in the ORM by theSession.scalar()
method ofSession
. (Background on SQLAlchemy 2.0 at: Migrating to SQLAlchemy 2.0)This first calls
FunctionElement.select()
to produce a SELECT construct.Note that
FunctionElement
can be passed to theConnectable.scalar()
method ofConnection
orEngine
.method
sqlalchemy.sql.functions.FunctionElement.
scalar_table_valued
(name, type_=None)Return a column expression that’s against this
FunctionElement
as a scalar table-valued expression.The returned expression is similar to that returned by a single column accessed off of a
FunctionElement.table_valued()
construct, except no FROM clause is generated; the function is rendered in the similar way as a scalar subquery.E.g.:
>>> from sqlalchemy import func, select
>>> fn = func.jsonb_each("{'k', 'v'}").scalar_table_valued("key")
>>> print(select(fn))
SELECT (jsonb_each(:jsonb_each_1)).key
New in version 1.4.0b2.
See also
method
sqlalchemy.sql.functions.FunctionElement.
select
()Produce a
select()
construct against thisFunctionElement
.This is shorthand for:
s = select(function_element)
method
sqlalchemy.sql.functions.FunctionElement.
self_group
(against=None)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.functions.FunctionElement.
table_valued
(\expr, **kw*)Return a
TableValuedAlias
representation of thisFunctionElement
with table-valued expressions added.e.g.:
>>> fn = (
... func.generate_series(1, 5).
... table_valued("value", "start", "stop", "step")
... )
>>> print(select(fn))
SELECT anon_1.value, anon_1.start, anon_1.stop, anon_1.step
FROM generate_series(:generate_series_1, :generate_series_2) AS anon_1
>>> print(select(fn.c.value, fn.c.stop).where(fn.c.value > 2))
SELECT anon_1.value, anon_1.stop
FROM generate_series(:generate_series_1, :generate_series_2) AS anon_1
WHERE anon_1.value > :value_1
A WITH ORDINALITY expression may be generated by passing the keyword argument “with_ordinality”:
>>> fn = func.generate_series(4, 1, -1).table_valued("gen", with_ordinality="ordinality")
>>> print(select(fn))
SELECT anon_1.gen, anon_1.ordinality
FROM generate_series(:generate_series_1, :generate_series_2, :generate_series_3) WITH ORDINALITY AS anon_1
Parameters
*expr – A series of string column names that will be added to the
.c
collection of the resultingTableValuedAlias
construct as columns.column()
objects with or without datatypes may also be used.name – optional name to assign to the alias name that’s generated. If omitted, a unique anonymizing name is used.
with_ordinality – string name that when present results in the
WITH ORDINALITY
clause being added to the alias, and the given string name will be added as a column to the .c collection of the resultingTableValuedAlias
.
New in version 1.4.0b2.
See also
[Table-Valued Functions]($cfdc81b69abe0678.md#tutorial-functions-table-valued) - in the [SQLAlchemy 1.4 / 2.0 Tutorial]($2006f9816d864d8d.md#unified-tutorial)
[Table-Valued Functions]($d951abc5c7ad81e4.md#postgresql-table-valued) - in the [PostgreSQL]($d951abc5c7ad81e4.md) documentation
[`FunctionElement.scalar_table_valued()`](#sqlalchemy.sql.functions.FunctionElement.scalar_table_valued "sqlalchemy.sql.functions.FunctionElement.scalar_table_valued") - variant of [`FunctionElement.table_valued()`](#sqlalchemy.sql.functions.FunctionElement.table_valued "sqlalchemy.sql.functions.FunctionElement.table_valued") which delivers the complete table valued expression as a scalar column expression
[`FunctionElement.column_valued()`](#sqlalchemy.sql.functions.FunctionElement.column_valued "sqlalchemy.sql.functions.FunctionElement.column_valued")
[`TableValuedAlias.render_derived()`]($fc2d211e9d1454ca.md#sqlalchemy.sql.expression.TableValuedAlias.render_derived "sqlalchemy.sql.expression.TableValuedAlias.render_derived") - renders the alias using a derived column clause, e.g. `AS name(col1, col2, ...)`
method
sqlalchemy.sql.functions.FunctionElement.
within_group
(\order_by*)Produce a WITHIN GROUP (ORDER BY expr) clause against this function.
Used against so-called “ordered set aggregate” and “hypothetical set aggregate” functions, including
percentile_cont
,rank
,dense_rank
, etc.See
within_group()
for a full description.New in version 1.1.
See also
Special Modifiers WITHIN GROUP, FILTER - in the SQLAlchemy 1.4 / 2.0 Tutorial
method
sqlalchemy.sql.functions.FunctionElement.
within_group_type
(within_group)For types that define their return type as based on the criteria within a WITHIN GROUP (ORDER BY) expression, called by the
WithinGroup
construct.Returns None by default, in which case the function’s normal
.type
is used.
class sqlalchemy.sql.functions.``GenericFunction
(\args, **kwargs*)
Define a ‘generic’ function.
A generic function is a pre-established Function
class that is instantiated automatically when called by name from the func
attribute. Note that calling any name from func
has the effect that a new Function
instance is created automatically, given that name. The primary use case for defining a GenericFunction
class is so that a function of a particular name may be given a fixed return type. It can also include custom argument parsing schemes as well as additional methods.
Subclasses of GenericFunction
are automatically registered under the name of the class. For example, a user-defined function as_utc()
would be available immediately:
from sqlalchemy.sql.functions import GenericFunction
from sqlalchemy.types import DateTime
class as_utc(GenericFunction):
type = DateTime
print(select(func.as_utc()))
User-defined generic functions can be organized into packages by specifying the “package” attribute when defining GenericFunction
. Third party libraries containing many functions may want to use this in order to avoid name conflicts with other systems. For example, if our as_utc()
function were part of a package “time”:
class as_utc(GenericFunction):
type = DateTime
package = "time"
The above function would be available from func
using the package name time
:
print(select(func.time.as_utc()))
A final option is to allow the function to be accessed from one name in func
but to render as a different name. The identifier
attribute will override the name used to access the function as loaded from func
, but will retain the usage of name
as the rendered name:
class GeoBuffer(GenericFunction):
type = Geometry
package = "geo"
name = "ST_Buffer"
identifier = "buffer"
The above function will render as follows:
>>> print(func.geo.buffer())
ST_Buffer()
The name will be rendered as is, however without quoting unless the name contains special characters that require quoting. To force quoting on or off for the name, use the quoted_name
construct:
from sqlalchemy.sql import quoted_name
class GeoBuffer(GenericFunction):
type = Geometry
package = "geo"
name = quoted_name("ST_Buffer", True)
identifier = "buffer"
The above function will render as:
>>> print(func.geo.buffer())
"ST_Buffer"()
New in version 1.3.13: The quoted_name
construct is now recognized for quoting when used with the “name” attribute of the object, so that quoting can be forced on or off for the function name.
Class signature
class sqlalchemy.sql.functions.GenericFunction
(sqlalchemy.sql.functions.Function
)
class sqlalchemy.sql.functions.``OrderedSetAgg
(\args, **kwargs*)
Define a function where the return type is based on the sort expression type as defined by the expression passed to the FunctionElement.within_group()
method.
Class signature
class sqlalchemy.sql.functions.OrderedSetAgg
(sqlalchemy.sql.functions.GenericFunction
)
method
sqlalchemy.sql.functions.OrderedSetAgg.
within_group_type
(within_group)For types that define their return type as based on the criteria within a WITHIN GROUP (ORDER BY) expression, called by the
WithinGroup
construct.Returns None by default, in which case the function’s normal
.type
is used.
class sqlalchemy.sql.functions.``ReturnTypeFromArgs
(\args, **kwargs*)
Define a function whose return type is the same as its arguments.
Class signature
class sqlalchemy.sql.functions.ReturnTypeFromArgs
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``ScalarFunctionColumn
(fn, name, type_=None)
Class signature
class sqlalchemy.sql.functions.ScalarFunctionColumn
(sqlalchemy.sql.expression.NamedColumn
)
class sqlalchemy.sql.functions.``array_agg
(\args, **kwargs*)
Support for the ARRAY_AGG function.
The func.array_agg(expr)
construct returns an expression of type ARRAY
.
e.g.:
stmt = select(func.array_agg(table.c.values)[2:5])
New in version 1.1.
See also
array_agg()
- PostgreSQL-specific version that returns ARRAY
, which has PG-specific operators added.
Class signature
class sqlalchemy.sql.functions.array_agg
(sqlalchemy.sql.functions.GenericFunction
)
attribute
sqlalchemy.sql.functions.array_agg.
type
alias of
sqlalchemy.sql.sqltypes.ARRAY
class sqlalchemy.sql.functions.``char_length
(arg, \*kwargs*)
The CHAR_LENGTH() SQL function.
Class signature
class sqlalchemy.sql.functions.char_length
(sqlalchemy.sql.functions.GenericFunction
)
attribute
sqlalchemy.sql.functions.char_length.
type
alias of
sqlalchemy.sql.sqltypes.Integer
class sqlalchemy.sql.functions.``coalesce
(\args, **kwargs*)
Class signature
class sqlalchemy.sql.functions.coalesce
(sqlalchemy.sql.functions.ReturnTypeFromArgs
)
class sqlalchemy.sql.functions.``concat
(\args, **kwargs*)
The SQL CONCAT() function, which concatenates strings.
E.g.:
>>> print(select(func.concat('a', 'b')))
SELECT concat(:concat_2, :concat_3) AS concat_1
String concatenation in SQLAlchemy is more commonly available using the Python +
operator with string datatypes, which will render a backend-specific concatenation operator, such as
>>> print(select(literal("a") + "b"))
SELECT :param_1 || :param_2 AS anon_1
Class signature
class sqlalchemy.sql.functions.concat
(sqlalchemy.sql.functions.GenericFunction
)
attribute
sqlalchemy.sql.functions.concat.
type
alias of
sqlalchemy.sql.sqltypes.String
class sqlalchemy.sql.functions.``count
(expression=None, \*kwargs*)
The ANSI COUNT aggregate function. With no arguments, emits COUNT *.
E.g.:
from sqlalchemy import func
from sqlalchemy import select
from sqlalchemy import table, column
my_table = table('some_table', column('id'))
stmt = select(func.count()).select_from(my_table)
Executing stmt
would emit:
SELECT count(*) AS count_1
FROM some_table
Class signature
class sqlalchemy.sql.functions.count
(sqlalchemy.sql.functions.GenericFunction
)
attribute
sqlalchemy.sql.functions.count.
type
alias of
sqlalchemy.sql.sqltypes.Integer
class sqlalchemy.sql.functions.``cube
(\args, **kwargs*)
Implement the CUBE
grouping operation.
This function is used as part of the GROUP BY of a statement, e.g. Select.group_by()
:
stmt = select(
func.sum(table.c.value), table.c.col_1, table.c.col_2
).group_by(func.cube(table.c.col_1, table.c.col_2))
New in version 1.2.
Class signature
class sqlalchemy.sql.functions.cube
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``cume_dist
(\args, **kwargs*)
Implement the cume_dist
hypothetical-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is Numeric
.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.cume_dist
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``current_date
(\args, **kwargs*)
The CURRENT_DATE() SQL function.
Class signature
class sqlalchemy.sql.functions.current_date
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.current_date.
type
alias of
sqlalchemy.sql.sqltypes.Date
class sqlalchemy.sql.functions.``current_time
(\args, **kwargs*)
The CURRENT_TIME() SQL function.
Class signature
class sqlalchemy.sql.functions.current_time
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.current_time.
type
alias of
sqlalchemy.sql.sqltypes.Time
class sqlalchemy.sql.functions.``current_timestamp
(\args, **kwargs*)
The CURRENT_TIMESTAMP() SQL function.
Class signature
class sqlalchemy.sql.functions.current_timestamp
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.current_timestamp.
type
alias of
sqlalchemy.sql.sqltypes.DateTime
class sqlalchemy.sql.functions.``current_user
(\args, **kwargs*)
The CURRENT_USER() SQL function.
Class signature
class sqlalchemy.sql.functions.current_user
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.current_user.
type
alias of
sqlalchemy.sql.sqltypes.String
class sqlalchemy.sql.functions.``dense_rank
(\args, **kwargs*)
Implement the dense_rank
hypothetical-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is Integer
.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.dense_rank
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``grouping_sets
(\args, **kwargs*)
Implement the GROUPING SETS
grouping operation.
This function is used as part of the GROUP BY of a statement, e.g. Select.group_by()
:
stmt = select(
func.sum(table.c.value), table.c.col_1, table.c.col_2
).group_by(func.grouping_sets(table.c.col_1, table.c.col_2))
In order to group by multiple sets, use the tuple_()
construct:
from sqlalchemy import tuple_
stmt = select(
func.sum(table.c.value),
table.c.col_1, table.c.col_2,
table.c.col_3
).group_by(
func.grouping_sets(
tuple_(table.c.col_1, table.c.col_2),
tuple_(table.c.value, table.c.col_3),
)
)
New in version 1.2.
Class signature
class sqlalchemy.sql.functions.grouping_sets
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``localtime
(\args, **kwargs*)
The localtime() SQL function.
Class signature
class sqlalchemy.sql.functions.localtime
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.localtime.
type
alias of
sqlalchemy.sql.sqltypes.DateTime
class sqlalchemy.sql.functions.``localtimestamp
(\args, **kwargs*)
The localtimestamp() SQL function.
Class signature
class sqlalchemy.sql.functions.localtimestamp
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.localtimestamp.
type
alias of
sqlalchemy.sql.sqltypes.DateTime
class sqlalchemy.sql.functions.``max
(\args, **kwargs*)
The SQL MAX() aggregate function.
Class signature
class sqlalchemy.sql.functions.max
(sqlalchemy.sql.functions.ReturnTypeFromArgs
)
class sqlalchemy.sql.functions.``min
(\args, **kwargs*)
The SQL MIN() aggregate function.
Class signature
class sqlalchemy.sql.functions.min
(sqlalchemy.sql.functions.ReturnTypeFromArgs
)
class sqlalchemy.sql.functions.``mode
(\args, **kwargs*)
Implement the mode
ordered-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is the same as the sort expression.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.mode
(sqlalchemy.sql.functions.OrderedSetAgg
)
class sqlalchemy.sql.functions.``next_value
(seq, \*kw*)
Represent the ‘next value’, given a Sequence
as its single argument.
Compiles into the appropriate function on each backend, or will raise NotImplementedError if used on a backend that does not provide support for sequences.
Class signature
class sqlalchemy.sql.functions.next_value
(sqlalchemy.sql.functions.GenericFunction
)
method
sqlalchemy.sql.functions.next_value.
compare
(other, \*kw*)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
).
class sqlalchemy.sql.functions.``now
(\args, **kwargs*)
The SQL now() datetime function.
SQLAlchemy dialects will usually render this particular function in a backend-specific way, such as rendering it as CURRENT_TIMESTAMP
.
Class signature
class sqlalchemy.sql.functions.now
(sqlalchemy.sql.functions.GenericFunction
)
attribute
sqlalchemy.sql.functions.now.
type
alias of
sqlalchemy.sql.sqltypes.DateTime
class sqlalchemy.sql.functions.``percent_rank
(\args, **kwargs*)
Implement the percent_rank
hypothetical-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is Numeric
.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.percent_rank
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``percentile_cont
(\args, **kwargs*)
Implement the percentile_cont
ordered-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is the same as the sort expression, or if the arguments are an array, an ARRAY
of the sort expression’s type.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.percentile_cont
(sqlalchemy.sql.functions.OrderedSetAgg
)
class sqlalchemy.sql.functions.``percentile_disc
(\args, **kwargs*)
Implement the percentile_disc
ordered-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is the same as the sort expression, or if the arguments are an array, an ARRAY
of the sort expression’s type.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.percentile_disc
(sqlalchemy.sql.functions.OrderedSetAgg
)
class sqlalchemy.sql.functions.``random
(\args, **kwargs*)
The RANDOM() SQL function.
Class signature
class sqlalchemy.sql.functions.random
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``rank
(\args, **kwargs*)
Implement the rank
hypothetical-set aggregate function.
This function must be used with the FunctionElement.within_group()
modifier to supply a sort expression to operate upon.
The return type of this function is Integer
.
New in version 1.1.
Class signature
class sqlalchemy.sql.functions.rank
(sqlalchemy.sql.functions.GenericFunction
)
function sqlalchemy.sql.functions.``register_function
(identifier, fn, package=’_default’)
Associate a callable with a particular func. name.
This is normally called by _GenericMeta, but is also available by itself so that a non-Function construct can be associated with the func
accessor (i.e. CAST, EXTRACT).
class sqlalchemy.sql.functions.``rollup
(\args, **kwargs*)
Implement the ROLLUP
grouping operation.
This function is used as part of the GROUP BY of a statement, e.g. Select.group_by()
:
stmt = select(
func.sum(table.c.value), table.c.col_1, table.c.col_2
).group_by(func.rollup(table.c.col_1, table.c.col_2))
New in version 1.2.
Class signature
class sqlalchemy.sql.functions.rollup
(sqlalchemy.sql.functions.GenericFunction
)
class sqlalchemy.sql.functions.``session_user
(\args, **kwargs*)
The SESSION_USER() SQL function.
Class signature
class sqlalchemy.sql.functions.session_user
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.session_user.
type
alias of
sqlalchemy.sql.sqltypes.String
class sqlalchemy.sql.functions.``sum
(\args, **kwargs*)
The SQL SUM() aggregate function.
Class signature
class sqlalchemy.sql.functions.sum
(sqlalchemy.sql.functions.ReturnTypeFromArgs
)
class sqlalchemy.sql.functions.``sysdate
(\args, **kwargs*)
The SYSDATE() SQL function.
Class signature
class sqlalchemy.sql.functions.sysdate
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.sysdate.
type
alias of
sqlalchemy.sql.sqltypes.DateTime
class sqlalchemy.sql.functions.``user
(\args, **kwargs*)
The USER() SQL function.
Class signature
class sqlalchemy.sql.functions.user
(sqlalchemy.sql.functions.AnsiFunction
)
attribute
sqlalchemy.sql.functions.user.
type
alias of
sqlalchemy.sql.sqltypes.String