DROP FUNCTION

DROP FUNCTION
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DROP FUNCTION — remove a function

Synopsis

+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. If no + argument list is specified, the name must be unique in its schema. +
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), + and in turn all objects that depend on those objects + (see Section 5.14). +
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);
+

+ Drop multiple functions in one command: +

+DROP FUNCTION sqrt(integer), sqrt(bigint);
+

+ If the function name is unique in its schema, it can be referred to without + an argument list: +

+DROP FUNCTION update_employee_salaries;
+

+ Note that this is different from +

+DROP FUNCTION update_employee_salaries();
+

+ which refers to a function with zero arguments, whereas the first variant + can refer to a function with any number of arguments, including zero, as + long as the name is unique. +

Compatibility

+ This command conforms to the SQL standard, with + these PostgreSQL extensions: +

The standard only allows one function to be dropped per command.
The IF EXISTS option
The ability to specify argument modes and names