那就像
IsNull(FieldName, 0)
或更完整地说：
SELECt iar.Description, ISNULL(iai.Quantity,0) as Quantity, ISNULL(iai.Quantity * rpl.RegularPrice,0) as 'Retail', iar.Compliance FROM InventoryAdjustmentReason iarLEFT OUTER JOIN InventoryAdjustmentItem iai on (iar.Id = iai.InventoryAdjustmentReasonId)LEFT OUTER JOIN Item i on (i.Id = iai.ItemId)LEFT OUTER JOIN ReportPriceLookup rpl on (rpl.SkuNumber = i.SkuNo)WHERe iar.StoreUse = 'yes'
