Question

伙计们，我已经阅读了这个问题的修复程序，但我有一个我无法解决的变体。

首先，以下语法抛出错误

 Case
    when #TFs.lTFID = 1161165 then REPLACE(CONVERT(VARCHAR(11), cast([dCreatedUTC] as datetime), 106), ' ', '-')
    when #TFs.lTFID = 1161166 then 'Administrator'
    when #TFs.lTFID = 1161167 then ''
    when #TFs.lTFID = 1161168 then AssetID
    when #TFs.lTFID = 1161169 then ''
    when #TFs.lTFID = 1161170 then ''
    when #TFs.lTFID = 1161172 then ''
    when #TFs.lTFID = 1161173 then ''
    else CAST(#TFs.lTFID as varchar(20))
  End 'Value'

如果我注释掉除了其中一条“when”行以外的所有行，它就会起作用。

 Case
    when #TFs.lTFID = 1161165 then REPLACE(CONVERT(VARCHAR(11), cast([dCreatedUTC] as datetime), 106), ' ', '-')
/*  when #TFs.lTFID = 1161166 then 'Administrator'
    when #TFs.lTFID = 1161167 then ''
    when #TFs.lTFID = 1161168 then AssetID
    when #TFs.lTFID = 1161169 then ''
    when #TFs.lTFID = 1161170 then ''
    when #TFs.lTFID = 1161172 then ''
    when #TFs.lTFID = 1161173 then ''*/
    else CAST(#TFs.lTFID as varchar(20))
  End 'Value'

有关如何格式化此查询以使所有“案例”都有效的任何想法？

Answer 1

根据错误消息，CASE表达式的结果将转换为INT。除了WHEN之外，VARCHAR的返回值也称为AssetID，因此我认为这必须是INT值。

发生错误是因为使用CASE表达式时，所有返回值必须是相同的数据类型。如果它们具有不同的数据类型，则所有值都将转换为具有更高data type precedence的类型。

由于INT的优先级高于VARCHAR，因此结果会转换为导致错误的INT。要解决此问题，您还必须将AssetID转换为VARCHAR(n)

Case
    when #TFs.lTFID = 1161165 then REPLACE(CONVERT(VARCHAR(11), cast([dCreatedUTC] as datetime), 106), ' ', '-')
    when #TFs.lTFID = 1161166 then 'Administrator'
    when #TFs.lTFID = 1161167 then ''
    when #TFs.lTFID = 1161168 then CAST(AssetID AS VARCHAR(20))
    when #TFs.lTFID = 1161169 then ''
    when #TFs.lTFID = 1161170 then ''
    when #TFs.lTFID = 1161172 then ''
    when #TFs.lTFID = 1161173 then ''
    else CAST(#TFs.lTFID as varchar(20))
End 'Value'

Answer 2

尝试将AssetID转换为case语句中的varchar。

Case
    when #TFs.lTFID = 1161165 then REPLACE(CONVERT(VARCHAR(11), cast([dCreatedUTC] as datetime), 106), ' ', '-')
    when #TFs.lTFID = 1161166 then 'Administrator'
    when #TFs.lTFID = 1161167 then ''
    when #TFs.lTFID = 1161168 then CAST(AssetID AS VARCHAR(20))
    when #TFs.lTFID = 1161169 then ''
    when #TFs.lTFID = 1161170 then ''
    when #TFs.lTFID = 1161172 then ''
    when #TFs.lTFID = 1161173 then ''
    else CAST(#TFs.lTFID as varchar(20))
  End 'Value'

Answer 3

试试这个

Case #TFs.lTFID
 When 1161165 then REPLACE(CONVERT(VARCHAR(11), cast([dCreatedUTC] as datetime), 106), ' ', '-')
 When 1161166 then 'Administrator'
 .
 .
 .
 Else CAST(#TFs.lTFID as varchar(20)) END

Answer 4

将CAST放在CASE之外，如下所示：

     CAST(
             Case
                when #TFs.lTFID = 1161165 then REPLACE(CONVERT(VARCHAR(11), cast([dCreatedUTC] as datetime), 106), ' ', '-')
                when #TFs.lTFID = 1161166 then 'Administrator'
                when #TFs.lTFID = 1161167 then ''
                when #TFs.lTFID = 1161168 then AssetID
                when #TFs.lTFID = 1161169 then ''
                when #TFs.lTFID = 1161170 then ''
                when #TFs.lTFID = 1161172 then ''
                when #TFs.lTFID = 1161173 then ''
                else #TFs.lTFID
              End 
         as varchar(20)) 'Value'

将varchar值转换为数据类型int时，SQL Select Case Conversion失败。

4 个答案: