SQL Syntax Reference : DROP FUNCTION
 
DROP FUNCTION
The DROP FUNCTION statement removes an existing user-defined function (UDF) from the database.
Note An error message appears if you attempt to delete a UDF that does not exist.
Syntax
DROP FUNCTION [ IF EXISTS ] { function_name }
 
function_name ::= Name of the user-defined function to be removed.
Remarks
The expression IF EXISTS causes the statement to return success instead of an error if a function does not exist. IF EXISTS does not suppress other errors.
Examples
The following statement drops UDF fn_MyFunc from the database.
DROP FUNCTION fn_MyFunc
See Also
CREATE FUNCTION