replace从左外连接返回的默认空值

我有一个Microsoft SQL Server 2008查询，使用左外连接从三个表中返回数据。 很多时候，第二个和第三个表中没有数据，所以我得到一个null，我认为它是左外连接的默认值。 有没有办法在select语句中replace默认值？ 我有一个解决方法，我可以select到一个表variables，但感觉有点肮脏。

SELECT iar.Description, iai.Quantity, iai.Quantity * rpl.RegularPrice as 'Retail', iar.Compliance FROM InventoryAdjustmentReason iar LEFT 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' 

如果可能，我希望Quantity和RegularPrice默认为零。

Answer 1

这很简单

 IsNull(FieldName, 0) 

或者更完全：

 SELECT iar.Description, ISNULL(iai.Quantity,0) as Quantity, ISNULL(iai.Quantity * rpl.RegularPrice,0) as 'Retail', iar.Compliance FROM InventoryAdjustmentReason iar LEFT 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' 

Answer 2

不是他的ISNULL，在这个IFNULL。

  SELECT iar.Description, IFNULL(iai.Quantity,0) as Quantity, IFNULL(iai.Quantity * rpl.RegularPrice,0) as 'Retail', iar.Compliance FROM InventoryAdjustmentReason iar LEFT 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'