Try

RETURN RIGHT(REPLICATE('0', 5) + @val, 5)

You may add the second parameter to UDF for the return size to make function more generic.

>Hi,
>
>i have code and is return zero, what do i miss to my code?
>
>alter FUNCTION RET_xxx (@val varchar(20))
>returns varchar
>AS

>begin
>	declare @ret varchar(20)
>	IF LEN(@val) = 1
>		set @ret= '0000'+@val
>	ELSE IF LEN(@val) = 2
>		set @ret=  '000'+@val
>	ELSE IF LEN(@val) = 3
>		set @ret=  '00'+@val
>	ELSE IF LEN(@val) >= 4
>		set @ret=  '0'+@val
>	RETURN(@ret)
>end