在1和表2场第

Question

我有一个查询：

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

但我想IN子句测试computerId太像这样：

LOGID = '1' 和 computerId = '998874'，

LOGID = '2' 和 computerId = '334211'， ...

如何做到这一点？

Answer 1

你将不得不使用多个替换IN声明OR声明

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

或者，如果你有很多的条件下，它可能是更具可读性为他们创建一个内存表，并在这些条件下加入

;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

我不认为你可以用IN条款做到这一点。我认为你需要一个有条件的地方。因此：

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

Answer 3

IN SQL Server不支持元组。您可以使用EXISTS和表格表达式。 2008语法如下。

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