在一个表上有两个字段的子句中

Question

我有一个查询:

 SELECT 
   MAX(date), 
   logId,
   computerId
 FROM 
   logTable
 WHERE logId IN ('1','2','3')

但是我希望IN子句也像这样测试computerId:

logId = ' 1 ' 和 computerId =‘998874’,

logId = '2' and computerId = '334211'，…

Answer 1

您必须将IN语句替换为多个OR语句

 SELECT  MAX(date)
        ,  logId
        , computerId
 FROM   logTable
 WHERE  (logId = '1' AND computerid = '998874')
        OR (logId = '2' AND computerid = '334211')

或者，如果您有许多条件，为它们创建一个内存表并在这些条件上连接可能更具可读性

;WITH Conditions (logID, computerid) AS (
  SELECT '1', '998874'
  UNION ALL SELECT '2', '334211'
)
SELECT  MAX(date)
        ,  logId
        , computerId
FROM   logTable lt
       INNER JOIN Conditions c ON c.logID = lt.LogID 
                                  AND c.computerid = lt.computerID

Answer 2

我不认为你可以这样做与IN条款。我觉得你需要一个有条件的位置。所以:

SELECT MAX(date), logId, computerId
FROM logTable
WHERE (logId = 1 AND computerId = '998874') OR
      (logId = 2 AND computerId = '334211') OR
      ...

Answer 3

SQL Server中的IN不支持元组。您可以使用EXISTS和表表达式。

SELECT MAX(l.date),
       l.logId,
       l.computerId
FROM   logTable l
WHERE  EXISTS(SELECT *
              FROM   (VALUES ( '1', '998874'),
                              ('2', '334211')) v(logId, computerId)
              WHERE  v.computerId = l.computerId
                     AND v.logId = l.logId)  
GROUP  BY l.logId,
          l.computerId  

Answer 4

像这样:

SELECT 
   MAX(date), 
   logId,
   computerId
 FROM 
   logTable
 WHERE (logId = '1' AND computerId = '998874')
    OR (logId = '2' AND computerId = '334211')
    OR (logId = '3' AND computerId = '123456')
 GROUP BY logId, computerId