1) Table 1 : TblOrder,
2) Table 2 : SubTblGreyFabricOrder,
3) Common field : "OrderID" in TblOrder and "OrderNumber" in SubTblGreyFabricOrder.
4) TblOrder has field : GreyPOQuantity which is in one to many relation with GreyPurchaseQualtity of Table SubTblGreyFabricOrder.
5) I want sum of...