UDF to return Years, Months & Days between 2 dates

/*
Returns the number of years, months and days between @startdate and @enddate in a single call but as a table
*/

CREATE FUNCTION udfElapsedDate (
@startdate SMALLDATETIME,
@enddate SMALLDATETIME
)  
RETURNS @retElapsed TABLE (Years SMALLINT, Months TINYINT, Days TINYINT) AS
BEGIN 
DECLARE @smonth TINYINT, @sday TINYINT, @syear SMALLINT
DECLARE @emonth TINYINT, @eday TINYINT, @eyear SMALLINT
DECLARE @months TINYINT, @days TINYINT, @years SMALLINT
DECLARE @tdate SMALLDATETIME
SET @smonth = MONTH(@startdate)
SET @sday = DAY(@startdate)
SET @syear = YEAR(@startdate)
SET @emonth = MONTH(@enddate)
SET @eday = DAY(@enddate)
SET @eyear = YEAR(@enddate)
SET @years = @eyear - @syear
SET @months = 0
SET @days = 0
IF (@emonth >= @smonth)
	SET @months = @emonth - @smonth
ELSE
	BEGIN
	SET @years = @years - 1
	SET @months = @emonth + 12 - @smonth
	END
IF (@eday >= @sday)
	SET @days = @eday - @sday
ELSE
	BEGIN
	IF (@months > 0)
		SET @months = @months - 1
	ELSE
		BEGIN
		SET @years = @years - 1
		SET @months = @months + 11
		END
	SET @tdate = DATEADD(yy,@years,@startdate)
	SET @tdate = DATEADD(m,@months,@tdate)
	SET @days = DATEDIFF(d,@tdate,@enddate)
	END
INSERT @retElapsed SELECT @years, @months, @days
RETURN
END

/*
Returns the number of years, months and days between @startdate and @enddate but only one for each of Y,M,D
Returns as an INT so can be used in a SELECT statement
*/

CREATE FUNCTION udfElapsedDatePart (
@startdate SMALLDATETIME,
@enddate SMALLDATETIME,
@period CHAR(1)  -- Must be 'Y', 'M' or 'D'
)
RETURNS INT AS
	BEGIN 
	DECLARE @smonth TINYINT, @sday TINYINT, @syear SMALLINT
	DECLARE @emonth TINYINT, @eday TINYINT, @eyear SMALLINT
	DECLARE @months TINYINT, @days TINYINT, @years SMALLINT
	DECLARE @tdate SMALLDATETIME, @ret INT
	SET @smonth = MONTH(@startdate)
	SET @sday = DAY(@startdate)
	SET @syear = YEAR(@startdate)
	SET @emonth = MONTH(@enddate)
	SET @eday = DAY(@enddate)
	SET @eyear = YEAR(@enddate)
	SET @years = @eyear - @syear
	SET @months = 0
	SET @days = 0
	IF (@emonth >= @smonth)
		SET @months = @emonth - @smonth
	ELSE
		BEGIN
		SET @years = @years - 1
		SET @months = @emonth + 12 - @smonth
		END
	IF (@eday >= @sday)
		SET @days = @eday - @sday
	ELSE
		BEGIN
		IF (@months > 0)
			SET @months = @months - 1
		ELSE
			BEGIN
			SET @years = @years - 1
			SET @months = @months + 11
			END
		SET @tdate = DATEADD(yy,@years,@startdate)
		SET @tdate = DATEADD(m,@months,@tdate)
		SET @days = DATEDIFF(d,@tdate,@enddate)
		END
	IF @period = 'Y'
		SET @ret = @years
	IF @period = 'M'
		SET @ret = @months
	IF @period = 'D'
		SET @ret = @days
	RETURN @ret
	END