mysql - 两次使用复合键连接表

Question

给定具有主键id 的表ticket 和具有复合键ticket,name 的表ticket_custom > 如何加入 id = ticket and name=X and id = ticket and name=Y。

ticket_custom 表允许扩展票表，它有字段ticket,name,value。

我可以做一个连接:

SELECT id, summary, owner, ticket_custom.value
FROM ticket
INNER JOIN ticket_custom
ON id=ticket_custom.ticket AND ticket_custom.name='X'

我需要这样的东西:

SELECT id, summary, owner, ticket_custom.value, ticket_custom.value
FROM ticket
INNER JOIN ticket_custom
ON id=ticket_custom.ticket AND ticket_custom.name='X' AND ticket_custom.name='Y'

第一个 ticket_custom.value 是 id,x 的值，第二个是 id,y 的值。

Answer 1

如果我没理解错的话，这就是你要找的:

SELECT id, summary, owner, c1.value, c2.value
FROM ticket t
INNER JOIN ticket_custom c1  ON t.id = c1.ticket AND c1.name = 'X'
INNER JOIN ticket_custom c2  ON t.id = c2.ticket AND c2.name = 'Y'