Question

我有一个CASE WHEN条件（CompanyGUID和LineGUID），我需要4个不同的计算4个不同的列。计算工作正常，但我只是想知道是否有任何方法可以使它更方便？例如，在这种情况下可能使用COALESCE技巧？

CASE WHEN dbo.tblCompanyLocations.CompanyGUID = '29634AF7-D0A2-473D-9574-405C23E10F02' 
      AND dbo.tblQuotes.LineGUID = '1CB72920-B3FC-4822-8030-37B50A2810EB' 
     THEN isnull(ddaWC.archexMod,1) 
     END as ExperienceMod, 

CASE WHEN dbo.tblCompanyLocations.CompanyGUID = '29634AF7-D0A2-473D-9574-405C23E10F02' 
      AND dbo.tblQuotes.LineGUID = '1CB72920-B3FC-4822-8030-37B50A2810EB'           
     THEN case when convert(int,ddawc.premModTtl) <= 0 then 1 
               when convert(int,ddawc.premModTtl) >= 0 
                 then (1 + ddaWC.premschmod / ddawc.premModTtl) end 
     END as ScheduleMod,

CASE WHEN dbo.tblCompanyLocations.CompanyGUID = '29634AF7-D0A2-473D-9574-405C23E10F02' 
      AND dbo.tblQuotes.LineGUID = '1CB72920-B3FC-4822-8030-37B50A2810EB'   
     THEN   isnull(ddaWC.TMpercent,1) END  as  TerritoryMod, 

CASE WHEN dbo.tblCompanyLocations.CompanyGUID = '29634AF7-D0A2-473D-9574-405C23E10F02' 
      AND dbo.tblQuotes.LineGUID = '1CB72920-B3FC-4822-8030-37B50A2810EB' 
     THEN case when convert(int,ddaWC.SchedPercent) = 0 or 
                    ddaWC.SchedPercent is not null 
                 then (isnull(ddaWC.archexMod,1) 
                     * (convert(decimal(5,2),isnull(ddaWC.SchedPercent,1)))) 
                     * isnull(ddaWC.TMpercent,1)
               when ddaWC.SchedPercent is null 
                  then 1 END 
     END as EffectiveMod

Answer 1

这样的东西？ OUTER APPLY将执行基于行的选择，如果您的条件未满，则返回NULLs。否则，它将返回您指定的相同值。只有当你真的需要为所有列提供相同的逻辑时，这才有效。

SELECT otherColumn
      ,ConditionalColumns.*
FROM YourTable
OUTER APPLY
(
    SELECT isnull(ddaWC.archexMod,1) as ExperienceMod, 
           case when convert(int,ddawc.premModTtl) <= 0 then 1 
                when convert(int,ddawc.premModTtl) >= 0 
                then (1 + ddaWC.premschmod / ddawc.premModTtl) end as ScheduleMod,
           isnull(ddaWC.TMpercent,1)  as  TerritoryMod, 
           case when convert(int,ddaWC.SchedPercent) = 0 or ddaWC.SchedPercent is not null 
                then (isnull(ddaWC.archexMod,1) 
                         * (convert(decimal(5,2),isnull(ddaWC.SchedPercent,1)))) 
                         * isnull(ddaWC.TMpercent,1)
                when ddaWC.SchedPercent is null 
                then 1 END as EffectiveMod
    WHERE dbo.tblCompanyLocations.CompanyGUID = '29634AF7-D0A2-473D-9574-405C23E10F02' 
          AND dbo.tblQuotes.LineGUID = '1CB72920-B3FC-4822-8030-37B50A2810EB' 
) AS ConditionalColumns

Answer 2

像这样：

代码前的某个地方：

Declare @compGuid char(37) = '29634AF7-D0A2-473D-9574-405C23E10F02' 
Declare @lineGuid char(37) = '1CB72920-B3FC-4822-8030-37B50A2810EB'

并修改SQL语句中的From Clause以定义别名
cl的{{1}}和 tblCompanyLocations的{{1}} 那么SQL代码的Select子句中的情况可以简化为：

有点可读......（检查逻辑）

嵌套的CASE WHEN语句

2 个答案: