Question

我会承认，小组总是给我带来问题，也许是因为我不明白它的正确使用，但希望一旦我看到它如何完成，我就会理解更多。

我的陈述：

SELECT DATENAME(month, A.[endTime]) as [month],
                   MONTH(A.[endTime]) as [monthValue],
                   (
                    SELECT count(employee) as attendees FROM Focus_Attendees WHERE meetingID = A.[id]
                   ) as attendees,
                   (
                    SELECT count(id) as totalMeetings FROM Focus_Meetings WHERE id = A.[id]
                   ) as totalMeetings

            FROM   Focus_Meetings as A
            WHERE YEAR(endTime) = @year
            GROUP BY DATENAME(month, A.[endTime]),  MONTH(A.[endTime])
            FOR XML PATH ('dataSet'), TYPE, ELEMENTS, ROOT ('root');

Column 'Focus_Meetings.id' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

我不想按ID对数据进行分组，因为每个结果都有一条单独的记录。我的桌子包含会议，我试图获得每月的会议总数，然后是那次会议的与会者人数。

通过调整声明来实现这一目标的任何建议？

更新

我将其更改为此查询：

        SELECT DATENAME(month, A.[endTime]) as [month],
               MONTH(A.[endTime]) as [monthValue],
               count(B.[employee]) as totalAttendees
        FROM   Focus_Meetings as A
        JOIN focus_attendees as B
        ON A.[id] = B.[meetingID]
        WHERE YEAR(endTime) = @year

        GROUP BY DATENAME(month, A.[endTime]),  MONTH(A.[endTime])
        FOR XML PATH ('dataSet'), TYPE, ELEMENTS, ROOT ('root');

这将返回我的XML：

`<root>
  <dataSet>
    <month>July</month>
    <monthValue>7</monthValue>
    <totalAttendees>1</totalAttendees>
  </dataSet>
  <dataSet>
    <month>June</month>
    <monthValue>6</monthValue>
    <totalAttendees>13</totalAttendees>
  </dataSet>
</root>`

这是正确的但我还需要那个月的会议总数count(A.[id])，但这会给我错误

Answer 1

现在您按日期分组，但尝试按ID选择计数。

第一个想法是将子选择包装在SUM中，以便一个月内所有会议的所有与会者将汇总在一起。

您的陈述：

SELECT count(id) as totalMeetings FROM Focus_Meetings WHERE id = A.[id]
                   ) as totalMeetings

毫无意义。如果id是主键，那么您将加入自己并始终获得1.只需将该行替换为count（*）即可获得一个月内的总会议数。

Answer 2

使用联接。

SELECT DATENAME(month, A.[endTime]) as [month],
       MONTH(A.[endTime]) as [monthValue],                   
       count(employee) ,
       count(distinct A.[Id]) 

 FROM  Focus_Meetings as A
       LEFT JOIN Focus_Attendees B ON B.meetingID = A.[id]
 WHERE YEAR(A.endTime) = @year
 GROUP BY DATENAME(month, A.[endTime]),  MONTH(A.[endTime])
 FOR XML PATH ('dataSet'), TYPE, ELEMENTS, ROOT ('root');

免责声明：我没有运行查询，因此可能需要进行一些小的调整。

TSQL Group with error with statement

2 个答案: