Problem in Query and DSUM function

[simplefahad2005]

I am using this query regarding stock card in my application but it is giving error undefined dsum expression. please help me in this regards. Thanks in Advance.


Query is mentioned below.
My query is below kindly help me.
Thanks in advance.

SELECT Stock_Card.StockCardID AS StockCardIDAlias, Stock_Card.StockID AS StockIDAlias, Stocks.Stock, Stock_Card.DateInsert, Stock_Card.ID, Stock_Card.Type, Stock_Card.RefNo1, Stock_Card.Pieces1, Stock_Card.Cost, [Stock_Card]![Cost]*[Pieces1] AS PurchaseAmount, Vendors.Company AS vendor, Stock_Card.RefNo2, Stock_Card.Pieces2, Stock_Card.SalesPrice, [Stock_Card]![SalesPrice]*[Pieces2] AS SalesAmount, Clients.Company AS client, Stock_Card.ICode,
DSum("[Pieces1]-[Pieces2]","Stock_Card","[StockCardID] <" & [StockCardIDAlias] & " And [StockID] = " & [StockIDAlias] & "") AS Previous, DSum("[Pieces1]-[Pieces2]","Stock_Card","[StockCardID] <=" & [StockCardIDAlias] & " And [StockID] = " & [StockIDAlias] & "") AS [On Hand]
FROM Clients RIGHT JOIN (Vendors RIGHT JOIN (Stock_Card LEFT JOIN Stocks ON Stock_Card.StockID = Stocks.StockID) ON Vendors.VendorId = Stock_Card.VendorID) ON Clients.ClientID = Stock_Card.ClientID;

[R_Badger]

It looks like you are trying to perform a calculation in the dsum, i think you need to perform the calculation by doing 2 dsums and then performing the calulcation.

[simplefahad2005]

Yes am doing calculation ind dsum.
Please tell me how to remove error "Undefined dsum expression".

Thanks

[R_Badger]

I'll try to reiterate.

The problem is you are trying to do a calculation in a DSUM, the function doesn't work like that read here. You have to DSUM each value and then perform the calculation.