SQL and Generic Functions¶
SQL functions are invoked by using the func namespace.
See the tutorial at Working with SQL Functions for background on how to
use the func object to render SQL functions in statements.
See also
Working with SQL Functions - in the SQLAlchemy 1.4 / 2.0 Tutorial
Function API¶
The base API for SQL functions, which provides for the func
namespace as well as classes that may be used for extensibility.
Selected “Known” Functions¶
These are GenericFunction implementations for a selected set of
common SQL functions that set up the expected return type for each function
automatically. The are invoked in the same way as any other member of the
func namespace:
select(func.count("*")).select_from(some_table)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.