SELECT cd.Id,d.Discount
FROM Cards cd
JOIN GETCLIENTDISCOUNT('01.05.03', 0 , 0 ) d ON (cd.Id = d.Id)

SELECT cd.Id,d.Discount
FROM Cards cd
JOIN GETCLIENTDISCOUNT(cd.Id, '01.05.03',  0 ,  0 ) d ON (cd.Id = d.Ret_CardId)

CREATE PROCEDURE GETCLIENTDISCOUNT(
DATEONLY DATE,
TOTAL DOUBLE PRECISION,
OPERID INTEGER)
RETURNS (
DISCOUNT DOUBLE PRECISION,
MAXSUM DOUBLE PRECISION,
CURRENTSUM DOUBLE PRECISION)
AS
declare variable StartDate1 DATE;
declare variable StartDate2 DATE;
declare variable EndDate1 DATE;
declare variable EndDate2 DATE;
declare variable DateTemp DATE;
declare variable CARDID VARCHAR( 16 );

declare variable Sum1 DOUBLE PRECISION;
declare variable Sum2 DOUBLE PRECISION;
declare variable Sum1_S DOUBLE PRECISION;
declare variable Sum2_S DOUBLE PRECISION;
declare variable Sum1_R DOUBLE PRECISION;
declare variable Sum2_R DOUBLE PRECISION;
begin

---------------------------------------------------------------------------
-- Цикл по Cards
FOR SELECT ID FROM Cards INTO :CardId DO BEGIN
-------------------------------------------------------------------------

 /*---------------------------------------------------------*/ 
 /*Сначала устанавливаем текущую дату*/ 
DateTemp = DateOnly;
StartDate1 = FirstDayMonth(DateTemp);
EndDate1 = LastDayMonth(DateTemp);

 /*Отнимаем один месяц*/ 
DateTemp = IncDate(StartDate1, 0 ,- 1 , 0 );
StartDate2 = FirstDayMonth(DateTemp);
EndDate2 = LastDayMonth(DateTemp);

 /*--Выбираем из 2-х месяцев максимальную сумму----*/ 
SELECT SUM(Actual)
FROM Opers
WHERE (CardId = :CardId)
AND (RDB$Modified <>  1 )
AND (DateOnly BETWEEN :StartDate1 AND :EndDate1)
AND (Id <> :OperId)
AND (ActionId <> 'R')
INTO :Sum1_S;
if (Sum1_S IS NULL) then Sum1_S =  0 ;

SELECT SUM(Actual)
FROM Opers
WHERE (CardId = :CardId)
AND (RDB$Modified <>  1 )
AND (DateOnly BETWEEN :StartDate1 AND :EndDate1)
AND (Id <> :OperId)
AND (ActionId = 'R')
INTO :Sum1_R;
if (Sum1_R IS NULL) then Sum1_R =  0 ;

Sum1 = Sum1_S - Sum1_R;

CURRENTSUM = Sum1;

SELECT SUM(Actual)
FROM Opers
WHERE (CardId = :CardId)
AND (RDB$Modified <>  1 )
AND (DateOnly BETWEEN :StartDate2 AND :EndDate2)
AND (Id <> :OperId)
AND (ActionId <> 'R')
INTO :Sum2_S;
if (Sum2_S IS NULL) then Sum2_S =  0 ;

SELECT SUM(Actual)
FROM Opers
WHERE (CardId = :CardId)
AND (RDB$Modified <>  1 )
AND (DateOnly BETWEEN :StartDate2 AND :EndDate2)
AND (Id <> :OperId)
AND (ActionId = 'R')
INTO :Sum2_R;
if (Sum2_R IS NULL) then Sum2_R =  0 ;

Sum2 = Sum2_S - Sum2_R;
 /*-------------------------------------------------*/ 

if (Sum1 > Sum2) then MaxSum = Sum1; else MaxSum = Sum2;
 /*MaxSum = MaxSum + Total;*/ 

 /*-----------Выбираем соответствующую скидку-------*/ 
SELECT MAX(Discount)
FROM DiscBarriers
WHERE (Barrier < :MaxSum)
INTO :Discount;

if (Discount IS NULL) then
 /*Сумма ниже всех барьеров, делаем скидку минимальной*/ 
begin
SELECT MIN(Discount)
FROM DiscBarriers
INTO :Discount;
end
suspend;
-------------------------------------------------------------------------
-- Конец цикла по Cards
-------------------------------------------------------------------------
END

end

SELECT cd.Id,d.Discount
FROM Cards cd
JOIN GETCLIENTDISCOUNT('01.05.03', 0 , 0 ) d ON (cd.Id = d.CardId)