在LEFT OUTER JOIN中替换返回的空值

Question

SELECT        WO_BreakerRail.ID, indRailType.RailType, indRailType.RailCode, WO_BreakerRail.CreatedPieces, WO_BreakerRail.OutsideSource, WO_BreakerRail.Charged, WO_BreakerRail.Rejected, WO_BreakerRail.RejectedToCrop, WO_BreakerRail.Date
FROM            indRailType LEFT OUTER JOIN
                         WO_BreakerRail ON indRailType.RailCode = WO_BreakerRail.RailCode AND WO_BreakerRail.Date = @date

返回时,Date列中有NULL值,其中没有来自WO_BreakerRail的匹配行.有没有办法用@date替换那些NULL值？

Answer 1

在oracle和sql server中，可以使用COALESCE（oracle版）函数

SELECT ...., COALESCE(WO_BreakerRail.Date, @date)