Question : converting null to zero

Hi,

The following sql statement works fine. How can I modify the stateent to retrive 'Sum_Order_Qty' to 0 if it is null?

        SELECT ol.PartNo, Model,CatName,
            p.PartName, Sum_Order_Qty, Sum_Stock, Sh_Qty,WH_Qty,RB_Qty,  
            Sum_Req_Qty, Avail_Qty = Sum_Stock + Sum_Order_Qty - Sum_Req_Qty
            FROM (SELECT PartNo, Sum(OQty) as Sum_Order_Qty FROM tblOrderDet GROUP BY PartNo) ol  
            LEFT JOIN tblSpareParts p ON p.PartNo = ol.PartNo  
            LEFT JOIN (SELECT PartNo, Sum(Qty) as Sum_Req_Qty FROM tblShortPartsList GROUP BY PartNo) sl  
            ON sl.PartNo = ol.PartNo
            JOIN (SELECT PartNo, Sum(OnHand) as Sum_Stock FROM tblStock GROUP BY PartNo) s  
            ON s.PartNo = ol.PartNo  
            LEFT JOIN (Select PartNo,OnHand as Sh_Qty from tblStock where storeid='SH') a ON ol.partno=a.partno  
            LEFT JOIN (Select PartNo,OnHand as WH_Qty from tblStock where storeid='WH') b ON ol.partno=b.partno  
            LEFT JOIN (Select PartNo,OnHand as RB_Qty from tblStock where storeid='RB') c ON ol.partno=c.partno  
            LEFT JOIN Models m ON p.MCode=m.MCode
            LEFT JOIN Categories ca ON p.CatCode=ca.CatCode

please help me with the sql statment?

ayha

Answer : converting null to zero

specifically...

FROM (SELECT PartNo, ISNULL(Sum(OQty), 0) as Sum_Order_Qty FROM tblOrderDet GROUP BY PartNo) ol