DROP FUNCTION [ IF EXISTS ] name ( [ [ argmode ] [ argname ] argtype [, ...] ] )
[ CASCADE | RESTRICT ]
Description
DROP FUNCTION removes the definition of an existing
function. To execute this command the user must be the
owner of the function. The argument types to the
function must be specified, since several different functions
can exist with the same name and different argument lists.
Parameters
IF EXISTS
Do not throw an error if the function does not exist. A notice is issued
in this case.
name
The name (optionally schema-qualified) of an existing function.
argmode
The mode of an argument: IN, OUT,
INOUT, or VARIADIC.
If omitted, the default is IN.
Note that DROP FUNCTION does not actually pay
any attention to OUT arguments, since only the input
arguments are needed to determine the function's identity.
So it is sufficient to list the IN, INOUT,
and VARIADIC arguments.
argname
The name of an argument.
Note that DROP FUNCTION does not actually pay
any attention to argument names, since only the argument data
types are needed to determine the function's identity.
argtype
The data type(s) of the function's arguments (optionally
schema-qualified), if any.
CASCADE
Automatically drop objects that depend on the function (such as
operators or triggers).
RESTRICT
Refuse to drop the function if any objects depend on it. This
is the default.
Examples
This command removes the square root function:
DROP FUNCTION sqrt(integer);
Compatibility
A DROP FUNCTION statement is defined in the SQL
standard, but it is not compatible with this command.