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MySQL对3个表的查询_Mysql_Sql_Join - Fatal编程技术网

MySQL对3个表的查询

MySQL对3个表的查询,mysql,sql,join,Mysql,Sql,Join,我在创建SQL查询时遇到了一些问题 我有以下表格: **Tour** tourID tourName **Schedule** scheduleID tourID **Ticket** scheduleID customerID 我要选择的是tourname和每次旅行的门票数量。我知道如何选择按时间表出售的门票数量,但我一直无法将其与巡演联系起来 每个时间表的门票数量: SELECT t.scheduleID, COUNT(t.scheduleID) AS numTickets FROM

我在创建SQL查询时遇到了一些问题

我有以下表格:

**Tour**
tourID
tourName

**Schedule**
scheduleID
tourID

**Ticket**
scheduleID
customerID
我要选择的是
tourname
和每次旅行的门票数量。我知道如何选择按时间表出售的门票数量,但我一直无法将其与巡演联系起来

每个时间表的门票数量:

SELECT t.scheduleID, COUNT(t.scheduleID) AS numTickets
FROM Ticket t
GROUP BY t.scheduleID
感谢您的帮助

尝试以下方法:

Select t.tourname, COUNT(tc.scheduleID) AS numTickets
From Tour t 
inner join Schedule s on t.tourID = s.tourID
inner join Ticket   tc on s.scheduleID = tc.scheduleID
group by t.tourID, t.tourname

太好了!非常感谢:)