DROP FUNCTION [ IF EXISTS ] [ owner.]function-name 

Use the IF EXISTS clause if you do not want an error returned when the DROP FUNCTION statement attempts to remove a function that does not exist.

DROP FUNCTION is prevented when the statement affects an object that is currently being used by another connection.

Any user who owns the object, or has DBA authority, can execute the DROP FUNCTION statement.

Automatic commit. Clears the Results tab in the Results pane in Interactive SQL.

• CREATE FUNCTION statement
• CREATE FUNCTION statement [External call]
• CREATE FUNCTION statement [Web service]
• ALTER FUNCTION statement

Drop MyFunction from the database. If the function does not exist, an error is returned.

DROP FUNCTION MyFunction;