我有三张桌子
Member - MemberID, gender, etc
Venue - VenueID, City, VenueName, etc
Event - EventID, EventDate, etc
尝试显示一个查询,显示城市为格拉斯哥的每个事件以及2012年1月的时间段内男性和女性的数量。
到目前为止我的结果是。
SELECT Venue.VenueName, Venue.City, Event.Eventdate, (select count(gender) from member where gender = 'm') AS MaleTotal, (select count(gender) from member where gender = 'f') AS FemaleTotal
FROM Venue INNER JOIN Event ON Venue.VenueID = Event.FKvenueID
WHERE Venue.City='Glagow' and Month(eventdate)=1 and year(partydate) = 2011;
这会生成一个显示
的表格VenueName-ABC Venue, XYZVenue;
City- Glasgow, Glasgow;
Partydate- 04/01/2012, 05/01/2012
MaleTotal-4,4
FemaleTotal-3,3
这是错误的,因为成员表中总共只有7个条目,每个条目只参加1个事件。
任何建议都将不胜感激。
答案 0 :(得分:0)
假设成员和事件之间存在多对多关系,您可以尝试这样的事情
SELECT Venue.VenueName,
Venue.City,
Event.Eventdate,
SUM (CASE gender WHEN 'm' THEN 1 ELSE 0 END) AS MaleTotal,
SUM (CASE gender WHEN 'f' THEN 1 ELSE 0 END) AS FemaleTotal
FROM Venue INNER JOIN
Event ON Venue.VenueID = Event.FKvenueID INNER JOIN
Event_Member ON Event_Member.EventID = Event.EventID INNER JOIN
Member ON Member.MemberID = Event_Member.MemberID
WHERE Venue.City='Glagow'
and Month(eventdate)=1
and year(partydate) = 2011
GROUP BY Venue.VenueName,
Venue.City,
Event.Eventdate