use [DATABASE]
IF EXISTS (SELECT 1 FROM sysobjects WHERE type = 'TF' AND name = '[function_name]')
BEGIN
   PRINT 'Dropping Function [function_name]'
   DROP FUNCTION [function_name]
END
GO
CREATE FUNCTION [function_name]
(
-- Parameter list
)
RETURNS
-- Returnvalue / table
AS
-- SQL Scrpit
GO
IF EXISTS (SELECT 1 FROM sysobjects WHERE type = 'TF' AND name = '[function_name]')
BEGIN
   PRINT 'Function [function_name] greated'
END
ELSE
BEGIN
   PRINT 'Function [function_name] not greated!'
END
GO