DROP FUNCTION

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 of the function must be specified, since several different functions may 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 of an existing function (optionally schema-qualified). 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

If the function has arguments, the data type(s) of the argument(s) (optionally schema-qualified).

CASCADE

Automatically drop objects that depend on the function (such as operators and triggers), and in turn all objects that depend on those objects.

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

DROP FUNCTION sqrt(integer);

Drop multiple functions in a single command:

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

# If the function name is unique in its schema, it can be referenced without an argument list:

DROP FUNCTION update_employee_salaries;

# Note that this is different from DROP FUNCTION update_employee_salaries();

# which references a function with zero arguments. The first variant can reference a function with any number of arguments, including zero, as long as the name is unique.

See Also

CREATE FUNCTION, ALTER FUNCTION, DROP PROCEDURE, DROP ROUTINE