GO
CREATE PROCEDURE dbo.DEMO @a as int, @b-2 as int out, @C as int output
AS
SET NOCOUNT ON
SET @b-2 = @a + 1
SET @C = @a * 5
Select @a as a, @b-2 as b, @C as c
RETURN @a
SET NOCOUNT OFF
GO
Declare @out1 as int
Declare @out2 as int
Declare @Return as int
Select @out1, @out2, @Return
--null, null, null
EXEC @Return = dbo.demo 2, @out1 output, @out2 output
--2,3,10
Select @out1, @out2, @Return
--3, 10, 2
DROP PROCEDURE DEMO