To drop a user-defined function, ,you must use the DROP FUNCTION statement. Listing 10.21 shows a simple example of this statement.
USE Northwind GO DROP FUNCTION dbo.Today
Before dropping a user-defined function, as with any other database object, check its dependencies.
You cannot drop a user-defined function if it is used in a constraint definition. If you drop a user-defined function and it is used in other functions, views, triggers, or stored procedures, those functions will produce an error on next execution.