Deleting a function v14

You can delete a function from the database using DROP FUNCTION.

DROP FUNCTION [ IF EXISTS ] <name> [ (<parameters>) ]
    [ CASCADE | RESTRICT ];

Where name is the name of the function to drop.

Specifying the parameter list is required in EDB Postgres Advanced Server under certain circumstances such as in an overloaded function. Oracle requires that you always omit the parameter list.
Use of IF EXISTS, CASCADE, or RESTRICT isn't compatible with Oracle databases. See the Database Compatibility: SQL for information on these options.

This example drops the function simple_function:

DROP FUNCTION simple_function;

Calling a function

Procedure and function parameters