Question

这是我的问题：

SELECT 
   dateTime, 
   AVG([timeTaken]) as avgtime, 
   MAX([timeTaken]) as maxtime, 
   COUNT(*) totalcalls
FROM 
   [Logs]
WHERE 
   csUriStem = '/REST/Issues/Issues.svc/' AND 
   [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
   (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)

执行时出现此错误：

Msg 8120，Level 16，State 1，Line 2
列'Logs.dateTime'在选择列表中无效，因为它不包含在聚合函数或GROUP BY子句中。

我理解为什么，但我的问题是，如何将关联的DateTime与相应的[MAX([timeTaken]) as maxtime]相关联？

Answer 1

好的，如果AVG列表中还有其他字段，那么MAX，COUNT和GROUP BY等汇总函数将需要某种SELECT 。这就是他们如何知道要操作的子集。所以，你需要做的就是 run ，这是这样的：

SELECT dateTime,
    AVG([timeTaken]) as avgtime,
    MAX([timeTaken]) as maxtime,
    COUNT(*) totalcalls
FROM [Logs]
WHERE 
    csUriStem = '/REST/Issues/Issues.svc/' AND 
    [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
    (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)
GROUP BY dateTime

但是，或者可能是您想要的。这将在AVG的每个分组上执行MAX，COUNT和dateTime over 。

然而，dateTime的这种分组可能是不合逻辑的;你可能想要这样的东西：

SELECT CONVERT(VARCHAR(8), dateTime, 101) AS groupDate,
    AVG([timeTaken]) as avgtime,
    MAX([timeTaken]) as maxtime,
    COUNT(*) totalcalls
FROM [Logs]
WHERE 
    csUriStem = '/REST/Issues/Issues.svc/' AND 
    [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
    (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)
GROUP BY CONVERT(VARCHAR(8), dateTime, 101)

这将按mm/dd/yy格式化该分组日期。

要进一步考虑使用聚合函数实际进行的操作，如果没有有任何其他字段：

SELECT AVG([timeTaken]) as avgtime,
    MAX([timeTaken]) as maxtime,
    COUNT(*) totalcalls
FROM [Logs]
WHERE 
    csUriStem = '/REST/Issues/Issues.svc/' AND 
    [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
    (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)

它仍然在组上运行。 组恰好是整个结果集。

Answer 2

您需要将其包含在group by子句

中

像这样。

SELECT 
    dateTime, 
    AVG([timeTaken]) as avgtime, 
    MAX([timeTaken]) as maxtime, 
    COUNT(*) totalcalls
  FROM 
    [Logs]
  WHERE
    csUriStem = '/REST/Issues/Issues.svc/' AND 
    [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
    (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)
  GROUP BY
    dateTime;

请注意，如果您需要有关平均值和最大值的信息，则需要将查询拆分为两个单独的查询。然后合并它们。

Answer 3

您需要在组中包含dateTime列，或者根据您的要求选择avg / max / min。

 SELECT dateTime, AVG([timeTaken]) as avgtime, MAX([timeTaken]) as maxtime, COUNT(*) totalcalls
      FROM [Logs]
      WHERE 
        csUriStem = '/REST/Issues/Issues.svc/' AND 
        [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
        (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)
      GROUP BY dateTime

Answer 4

如果您只想要一行，并且希望它的最大值为DateTime，那么您可以使用聚合order by和top执行此操作：

SELECT TOP 1 dateTime, AVG([timeTaken]) as avgtime, 
       MAX([timeTaken]) as maxtime, COUNT(*) totalcalls
FROM [Logs]
WHERE csUriStem = '/REST/Issues/Issues.svc/' AND 
      [dateTime] > DATEADD(MINUTE, -15, GETUTCDATE()) AND
      (csUserAgent != 'Fiddler' OR csUserAgent IS NULL)
GROUP BY dateTime
order by dateTime desc;

如何将列添加到聚合函数中

4 个答案: