Процедура определения остатка

create procedure ostscl;9
 @kod_tel int = NULL,
 @otdel int = NULL, 
 @Kol int = NULL  
as
select (sum(Nakladnay.Kol_telephonov)-sum(Chek.Kol_telephon)) AS Количество
from Nakladnay join Chek on (Nakladnay.kod_telephona=Chek.kod_telephona and Nakladnay.N_otdelenia= Chek.N_otdelenia) 
where (Nakladnay.kod_telephona=@kod_tel and Chek.kod_telephona =@kod_tel) and (Nakladnay.N_otdelenia=@otdel and Chek.N_otdelenia =@otdel) 
 
declare 
@kod_tel int, @Kol int, @otdel int
set @kod_tel=1
set @otdel=10
exec ostscl;9 @kod_tel, @Kol, @otdel

CREATE PROCEDURE ostscl 
   @kod_tel INT = NULL, @otdel INT = NULL, @Kol INT OUTPUT
AS
SELECT @Kol=n.kol - c.kol 
FROM (
    SELECT sum(n.Kol_telephonov) kol
    FROM Nakladnay n
    WHERE n.kod_telephona = @kod_tel AND n.N_otdelenia = @otdel
    ) n
CROSS JOIN (
    SELECT sum(c.Kol_telephon) kol
    FROM Chek c
    WHERE c.kod_telephona = @kod_tel AND c.N_otdelenia = @otdel
    ) c
GO

DECLARE @kod_tel INT, @otdel INT, @Kol INT
SELECT @kod_tel = 1, @otdel = 10
EXEC ostscl @kod_tel, @otdel, @Kol OUTPUT
SELECT @Kol