This query might help you

Create Table WHS_Details (ItemCode VarChar(20),

Quantity numeric(19, 6),

Price numeric(19, 6),

DocType VarChar(10),

DocNum VarChar(12),

DocDate Date ,

TransID Int)

Insert into WHS_Details values ('IT001',10,100,'PURCHASE',210000033,'2013-09-11',85)

Insert into WHS_Details values ('IT002',10,1000,'PURCHASE',210000033,'2013-09-11',85)

Insert into WHS_Details values ('IT001',6,200,'SALES',110000019,'2013-09-12',86)

Insert into WHS_Details values ('IT001',5,200,'PURCHASE',210000034,'2013-09-13',87)

Insert into WHS_Details values ('IT001',5,200,'SALES',110000019,'2013-09-14',88)

select ItemCode, Price, DocDate, SUM(Quantity) as Quantity into #availQty from WHS_Details

where DocType ='PURCHASE'

group by ItemCode, Price, DocDate

order by DocDate

alter table #availQty ADD id int identity(1,1)

declare @ItemCode VarChar(20),@Quantity numeric(19, 6), @id int, @availQty numeric(19, 6)

declare soldqty cursor for select ItemCode,Quantity from WHS_Details where DocType='SALES'

open soldqty

fetch soldQty into @ItemCode, @Quantity

while @@FETCH_STATUS = 0

begin

select top 1 @id=id, @availQty = Quantity from #availQty where ItemCode = @ItemCode

order by DocDate

if (@availQty < @Quantity)

begin

delete from #availQty where id=@id

set @Quantity = @Quantity - @availQty

end

select top 1 @id=id, @availQty = Quantity from #availQty where ItemCode = @ItemCode

order by DocDate

update #availQty set Quantity = Quantity - @Quantity where id=@id

fetch soldQty into @ItemCode, @Quantity

end

close soldqty

deallocate soldqty

select * from #availQty

drop table #availQty

drop table WHS_Details