Question

我有这个查询

SELECT  
    LineId, [LineNumber], 
    TotalNeed, TotalMRC, TotalMIV, TotalIMIV,
    (TotalMRC - TotalMIV) as Shortage
FROM  
    (SELECT  
         LineId,[LineNumber],
         ROUND(SUM(Quantity), 3) AS TotalNeed,
         SPMS2.dbo.ReturnTotalMRCByLineId(LineId) AS TotalMRC, 
         SPMS2.dbo.ReturnTotalMIVByLineId(LineId) AS TotalMIV,
         SPMS2.dbo.ReturnTotalIMIVByLineId(LineId) AS TotalIMIV
     FROM  
         [SPMS2].[dbo].[ViewMTO]
     GROUP BY 
         lineid, [LineNumber]) a

这些是结果：

正如您所看到的，我的一些列值为null。如果值0？

，如何将其设置为null

Answer 1

这是一个简单的方法：

  SELECT mto.LineId, mto.[LineNumber], round(sum(mto.Quantity), 3) as TotalNeed
         v.*, (v.TotalMRC - v.TotalMIV ) as Shortage
  FROM [SPMS2].[dbo].[ViewMTO] mto CROSS APPLY
       (VALUES (ISNULL(SPMS2.dbo.ReturnTotalMRCByLineId(mto.LineId), 0),
                ISNULL(SPMS2.dbo.ReturnTotalMIVByLineId(mto.LineId), 0),
                ISNULL(SPMS2.dbo.ReturnTotalIMIVByLineId(mto.LineId), 0)
               )
       ) v(TotalMRC, TotalMIV, TotalIMIV)
  GROUP BY mto.lineid, mto.[LineNumber];

通常情况下，我更喜欢COALESCE()到ISNULL()（因为前者是标准的）。但是，COALESCE()会对第一个参数进行两次计算。因此，对于昂贵的操作（例如用户定义的函数），ISNULL()更有效。

Answer 2

您可以使用coalesce将null替换为值：

SELECT  LineId,
        [LineNumber],
        TotalNeed,
        TotalMRC,
        TotalMIV,
        TotalIMIV,
        (TotalMRC - TotalMIV) as Shortage
  FROM  (
        SELECT  LineId,[LineNumber],
                round(sum(Quantity),3) as TotalNeed
                ,COALESCE(SPMS2.dbo.ReturnTotalMRCByLineId(LineId), 0) as TotalMRC
                ,COALESCE(SPMS2.dbo.ReturnTotalMIVByLineId(LineId), 0) as TotalMIV
                ,COALESCE(SPMS2.dbo.ReturnTotalIMIVByLineId(LineId), 0)  as TotalIMIV
          FROM  [SPMS2].[dbo].[ViewMTO]
          GROUP BY lineid,[LineNumber]
        ) a

在SQL Server中为空行设置零默认值

2 个答案: