我有一组显示体育裁判比赛时间表的数据。在几乎所有情况下，每场比赛有2名裁判在一起工作。这是我的疑问：
SELECT DISTINCT g.GroupName, date(s.EventDate) AS EventDate, DATE_FORMAT(s.EventDate,'%H:%i:%s') AS EventTime, l.SiteName, ss.SubSiteName, u.Email, u.FirstName, u.LastName, u.Phone1
FROM Schedule s
JOIN Groups g
ON s.GroupID = g.GroupID
LEFT OUTER JOIN Sites l
ON s.SiteID = l.SiteID
LEFT OUTER JOIN SubSites ss
ON l.SiteID = ss.SiteID
LEFT OUTER JOIN Users u
ON s.UserID = u.UserID
WHERE g.OrganizationID = 2
AND s.EventDate > DATE_ADD(NOW(), INTERVAL 0 HOUR)
AND (s.SubSiteID = 0 OR s.SubSiteID = ss.SubSiteID)
ORDER BY l.SiteName, ss.SubSiteName, s.EventDate, u.LastName
以下是该查询产生的一些记录：
GroupName EventDate EvtTime SiteName SubSite Email FirstName LastName Phone1
==============================================================================================================================
Hoops Forever 8/10/2016 8:00 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555
Hoops Forever 8/10/2016 8:00 Kennedy High School Court #33 BMJ ref2@yahoo.com Kris Jones 8013331111
Hoops Forever 8/10/2016 9:20 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555
Hoops Forever 8/10/2016 9:20 Kennedy High School Court #33 BMJ ref2@yahoo.com Kris Jones 8013331111
Hoops Forever 8/10/2016 10:40 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555
Hoops Forever 8/10/2016 10:40 Kennedy High School Court #33 BMJ ref3@yahoo.com Kassy Hanks 8019997777
Hoops Forever 8/10/2016 12:00 Kennedy High School Court #33 BMJ ref4@gmail.com Michael Rogers 8010001111
Hoops Forever 8/10/2016 12:00 Kennedy High School Court #33 BMJ ref2@yahoo.com Kris Jones 8013331111
Hoops Forever 8/10/2016 13:20 Kennedy High School Court #33 BMJ ref4@gmail.com Michael Rogers 8010001111
Hoops Forever 8/10/2016 13:20 Kennedy High School Court #33 BMJ ref2@yahoo.com Kris Jones 8013331111
现在查看前2行并注意除了最后4列（特定于裁判）之外，2行之间的所有值都相同。所以我尝试添加这个：
GROUP BY GroupName, EventDate, EvtTime, SiteName, SubSite
那让我走到了一半，但是我在每个分组中输掉了第二名裁判：
GroupName EventDate EvtTime SiteName SubSite Email FirstName LastName Phone1
==============================================================================================================================
Hoops Forever 8/10/2016 8:00 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555
Hoops Forever 8/10/2016 9:20 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555
Hoops Forever 8/10/2016 10:40 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555
Hoops Forever 8/10/2016 12:00 Kennedy High School Court #33 BMJ ref4@gmail.com Michael Rogers 8010001111
Hoops Forever 8/10/2016 13:20 Kennedy High School Court #33 BMJ ref4@gmail.com Michael Rogers 8010001111
不用多说，这就是我真正需要的东西：
GroupName EventDate EvtTime SiteName SubSite Email1 FN1 LN1 Phone1 EMail2 FN2 LN2 Phone2
=========================================================================================================================================================================
Hoops Forever 8/10/2016 8:00 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555 ref2@yahoo.com Kris Jones 8013331111
Hoops Forever 8/10/2016 9:20 Kennedy High School Court #33 BMJ ref1@comcast.net Jeff Smith 8014445555 ref2@yahoo.com Kris Jones 8013331111
etc...........
请注意，在我想要的结果集中，4个不同的列（ref-specific而不是游戏特定的）被附加到＆＃34;压缩＆＃34;行。逻辑上它是有道理的：有1个游戏，但有2个参考。我希望1个游戏的信息在1行中，我希望2个参考的信息也在同一行，附加到结尾。在实际的DB中有2行，但我希望它们合并并附加。如果没有裁判信息，我只想要空白/空白 - 没什么特别的。
那么为此构建的sql是怎么样的？非常感谢提前！
答案 0 :(得分：1)
如果可以将两个引用存储在同一列中，则可以使用：
GROUP_CONCAT(column SEPARATOR ',')
确定组中只有两行时的另一种解决方案：