SQL Server CASE .. WHEN .. IN 语句

Posted 2023-02-16

【中文标题】SQL Server CASE .. WHEN .. IN 语句

【英文标题】：SQL Server CASE .. WHEN .. IN statement

【发布时间】：2011-08-27 22:02:00

【问题描述】：

在 SQL Server 2005 上，我正在尝试查询此选择语句

SELECT AlarmEventTransactionTableTable.TxnID,
       CASE AlarmEventTransactions.DeviceID
         WHEN DeviceID IN( '7', '10', '62', '58',
                           '60', '46', '48', '50',
                           '137', '139', '142', '143', '164' )
           THEN '01'
         WHEN DeviceID IN( '8', '9', '63', '59',
                           '61', '47', '49', '51',
                           '138', '140', '141', '144', '165' )
           THEN '02'
         ELSE 'NA'
       END AS clocking,
       AlarmEventTransactionTable.DateTimeOfTxn
FROM   multiMAXTxn.dbo.AlarmEventTransactionTable 

它返回下面的错误

消息 156，级别 15，状态 1，第 4 行 关键字“IN”。

请就我的代码可能有什么问题给我一些建议。

【参考方案1】：

试试这个...

SELECT
    AlarmEventTransactionTableTable.TxnID,
    CASE
        WHEN DeviceID IN('7', '10', '62', '58', '60',
                 '46', '48', '50', '137', '139',
                 '142', '143', '164') THEN '01'
        WHEN DeviceID IN('8', '9', '63', '59', '61',
                 '47', '49', '51', '138', '140',
                 '141', '144', '165') THEN '02'
        ELSE 'NA' END AS clocking,
    AlarmEventTransactionTable.DateTimeOfTxn
 FROM
    multiMAXTxn.dbo.AlarmEventTransactionTable

只需删除突出显示的字符串

选择 AlarmEventTransactionTableTable.TxnID, 案例 AlarmEventTransactions.DeviceID WHEN DeviceID IN('7', '10', '62', '58', '60', ...)

【讨论】：

我已将它作为 CASE WHEN DeviceID IN('7', '10', '62', '58', '60', '46', '48', '50', ' 137', '139', '141', '145', '164') THEN '01' WHEN DeviceID IN('8', '9', '63', '59', '61','47' , '49', '51', '138', '140','142', '146', '165') THEN '02' ELSE 'NA' END AS clocking,

【参考方案2】：

CASE AlarmEventTransactions.DeviceID 应该只是 CASE。

你正在混音the 2 forms of the CASE expression。

【讨论】：

谢谢，我已将其修复为如下所示

【参考方案3】：

感谢您的回答 我已将语句修改为如下所示

SELECT
     AlarmEventTransactionTable.TxnID,
     CASE 
    WHEN DeviceID IN('7', '10', '62', '58', '60',
            '46', '48', '50', '137', '139',
             '141', '145', '164') THEN '01'
    WHEN DeviceID IN('8', '9', '63', '59', '61',
            '47', '49', '51', '138', '140',
            '142', '146', '165') THEN '02'
             ELSE 'NA' END AS clocking,
     AlarmEventTransactionTable.DateTimeOfTxn
FROM
     multiMAXTxn.dbo.AlarmEventTransactionTable

【参考方案4】：

使用“简单大小写”以手写方式写出时可能更容易阅读，例如

CASE DeviceID 
   WHEN '7  ' THEN '01'
   WHEN '10 ' THEN '01'
   WHEN '62 ' THEN '01'
   WHEN '58 ' THEN '01'
   WHEN '60 ' THEN '01'
   WHEN '46 ' THEN '01'
   WHEN '48 ' THEN '01'
   WHEN '50 ' THEN '01'
   WHEN '137' THEN '01'
   WHEN '139' THEN '01'
   WHEN '142' THEN '01'
   WHEN '143' THEN '01'
   WHEN '164' THEN '01'
   WHEN '8  ' THEN '02'
   WHEN '9  ' THEN '02'
   WHEN '63 ' THEN '02'
   WHEN '59 ' THEN '02'
   WHEN '61 ' THEN '02'
   WHEN '47 ' THEN '02'
   WHEN '49 ' THEN '02'
   WHEN '51 ' THEN '02'
   WHEN '138' THEN '02'
   WHEN '140' THEN '02'
   WHEN '141' THEN '02'
   WHEN '144' THEN '02'
   WHEN '165' THEN '02'
   ELSE 'NA' 
END AS clocking

...哪一种让我觉得也许你可以从一个查找表中受益，你可以通过JOIN 完全消除CASE 表达式。