CREATE PROC [dbo].[usp_spFactorial]
@InputValue INT,
@OuputValue INT OUTPUT
AS
BEGIN
   DECLARE @InValue  INT;
   DECLARE @OutValue  INT;
    IF(@InputValue!=1)
      BEGIN
         SET @InValue = @InputValue - 1;
         EXEC spFactorial @InValue,@OutValue OUTPUT;
         SELECT @OuputValue = @InputValue * @OutValue;
      END
    ELSE
      BEGIN
      SET @OuputValue = 1;
      END
END