DROP FUNCTION

Description

Deletes a function.

Precautions

If a function involves operations on temporary tables, DROP FUNCTION cannot be used.

Only the function owner or a user granted with the DROP permission can run the DROP FUNCTION command. The system administrator has this permission by default.

Syntax

    
         DROP FUNCTION [ IF EXISTS ] function_name 
[ ( [ { [ argname ] [ argmode ] argtype} [, ...] ] ) [ CASCADE | RESTRICT ] ];

Parameters

IF EXISTS
Reports a notice instead of an error if the specified function does not exist.
function_name
Specifies the name of the function to be deleted.

Value range: an existing function name
argmode
Specifies the parameter mode of the function.
argname
Specifies the parameter name of the function.
argtype
Specifies the parameter type of the function.
CASCADE | RESTRICT
- CASCADE: automatically deletes the objects that depend on the function.
- RESTRICT: refuses to delete the function if any objects depend on it. This is the default action.

Examples

Delete the list of parameters that can be omitted when a function.

-- Create a function.
gaussdb=# CREATE FUNCTION func_test(varchar) RETURN VARCHAR AS
BEGIN 
    RETURN $1||_'test';
END;
/

-- Delete the function.
gaussdb=# DROP FUNCTION func_test;

Delete a function with the same name.

If a function with the same name exists, add a parameter list when deleting the function. Otherwise, an error is reported.

-- Create a function.
gaussdb=# CREATE FUNCTION func_add(int) RETURNS int AS $$
BEGIN 
    RETURN $1+10;
END;
$$ LANGUAGE PLPGSQL;

-- Overload the func_add function.
gaussdb=# CREATE FUNCTION func_add(int,int) RETURNS int AS $$
BEGIN 
    RETURN $1+$2;
END;
$$ LANGUAGE PLPGSQL;

-- Delete the function.
gaussdb=# DROP FUNCTION func_add(int);
gaussdb=# DROP FUNCTION func_add(int,int);