CREATE FUNCTION fn_string_compare (
	@string1 VARCHAR(20), 
	@string2 VARCHAR(20)
)  
RETURNS INT
AS  

BEGIN 
	DECLARE
		@ok BIT,
		@index INT

	IF LEN(@string1) <> LEN(@string2) BEGIN
		RETURN -1
	END -- IF

	SET @ok = 1
	SET @index = 0
	WHILE @index < LEN(@string1) AND @ok = 1 BEGIN
		IF ASCII(SUBSTRING(@string1, @index, 1)) <> ASCII(SUBSTRING(@string2, @index, 1)) BEGIN
			SET @ok = 0
		END -- IF

		SET @index = @index + 1
	END -- WHILE

	IF @ok = 0 BEGIN
		RETURN -1
	END -- IF

	RETURN 0
END