Recursion in Stored Procedures

CREATE PROCEDURE Factorial_ap
@Number Integer,
@RetVal Integer OUTPUT
AS
BEGIN
DECLARE @In Integer, @Out Integer
IF @Number != 1
BEGIN 
SELECT @In = @Number-1
EXEC Factorial_ap @In, @Out OUTPUT
SELECT @RetVal = @Number * @Out
END
ELSE
BEGIN
SELECT @RetVal = 1
END	
RETURN @RetVal	
END
GO

DECLARE @RESULT Integer
SET @RESULT = 0
EXEC Factorial_ap 5, @RESULT OUTPUT
PRINT @RESULT

;WITH MyCTE AS
(
    --initial value
    SELECT 1 AS ID
    UNION ALL
    --recursive part 
    SELECT ID + 1 AS ID
    FROM MyCTE
    WHERE ID<100
)
SELECT ID
FROM MyCTE