My subject is to get the price from item which go into stock and put the price into out item by (FIFO order by TranDate) , then calculate the total price of any line of production (" lineid ") 

This is what i have done 

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-- temp table for result
declare @Test table ( stockID int , OriQty decimal(16,2)  ,inuse decimal(16,2) , price decimal(16,2) , lineid int , Inid int )

declare @StockIn table (ID int , StockID int ,qty decimal(16,2),Price decimal(16,2), tranDate Date , running int)
insert into @StockIn(ID , StockID , qty ,  Price , tranDate  , running) values

(1,1 , 15 , 430 , '2014-10-09' , 1),
(2,1 , 10 , 431, '2014-12-09' , 2),
(3,1 , 15 , 432, '2015-02-02' , 3),
(4,2 , 15 , 450, '2014-08-05' , 1),
(5,2 , 6 , 450, '2014-10-09' , 2),
(6,2 , 15 , 452, '2015-02-02' , 3)

-- lineid = line production
declare @StockOut table (ID int , StockID int ,qty decimal(16,2), lineid int, tranDate Date)
insert into @StockOut(ID , StockID  ,qty , lineid, tranDate ) 
values
(1,1 , 20 , 2, '2014-10-10'), 
(2,1 , 10 , 4, '2014-12-20'),
(3,2 , 12 , 8, '2014-10-01'),
(4,2 , 3 , 8, '2014-10-01') ;


DECLARE @intFlag INT 
SET @intFlag = 1 -- initial of loop

WHILE (@intFlag <= (Select Max(ID) from @StockOut) )
BEGIN
   
   declare @stockID int 
   declare @ids table (ID int , Inuse decimal(16,2))
   declare @lineid int 
   declare @qtyToRemove decimal(16,2) -- get qty from @StockOut 

   --get data from @StockOut row by row
   select @stockID = StockID  , @qtyToRemove = qty , @lineid = lineid from @StockOut where ID = @intFlag;
   
    with cte as (
 
   select *, sum(qty) over (order by tranDate ASC , qty DESC , tranDate ASC Rows UNBOUNDED PRECEDING) - @qtyToRemove
   as Total FROM @StockIn Where stockID = @stockID )

   -- running FIFO from  @StockIn and update QTy when stock is running out 
     , RunningFIFO as (
   select cte.StockID , cte.qty AS OriginalQty , Case when 
   case when  0 > total then cte.qty else cte.qty-total End > 0 then case when  0 > total then cte.qty else cte.qty-total End else 0 End As Inuse
   ,  cte.Price , @lineid AS lineid , id
   from cte 

   )


   -- insert result into result table
   insert into @test (stockID , OriQty ,inuse ,  cte.Price , lineid ,Inid ) OUTPUT inserted.Inid , inserted.inuse  into @ids select * from RunningFIFO Where Inuse > 0  
UPDATE @StockIn set qty = qty - inuse from @ids A inner join  @StockIn B on A.ID = b.ID
    
   SET @intFlag = @intFlag + 1

END


Select sum(inuse * price) AS total , lineid  from @Test group by lineid

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But when data are more than thousand , This query run super slow , Could you please help me increase the performance of this query. 

• Edited by Hemkoe 14 minutes ago