UFN_HOURMINUTE_GETFROMDATE

CREATE function dbo.UFN_HOURMINUTE_GETFROMDATE
(
    @DATETOCONVERT datetime
) returns char(4)
as
begin
    declare @HOURSTRING char(2);
    declare @MINUTESTRING char(2);
    declare @HOURVALUE int;
    declare @MINUTEVALUE int;

    select
        @HOURVALUE = DATEPART(hh, @DATETOCONVERT),
        @MINUTEVALUE = DATEPART(mi, @DATETOCONVERT);

    set @HOURSTRING = case
        when @HOURVALUE < 10 then '0' + CAST(@HOURVALUE as CHAR(1))
        else CAST(@HOURVALUE as CHAR(2))
        end;

    set @MINUTESTRING = case
        when @MINUTEVALUE < 10 then '0' + CAST(@MINUTEVALUE as CHAR(1))
        else CAST(@MINUTEVALUE as CHAR(2))
        end;

    return @HOURSTRING + @MINUTESTRING;
end