Question

我的桌子

GROUPS
----------
id | groupName
4    Personal
5    Friends
6    University


Records
----------
id | groupId  | name
1    4          Majid
2    4          Jawad
3    5          Zain
4    5          Mohsin
5    6          Ismail
7    6          Zubair


groups_connected
--------------------
id   |  parent_id  |  child_id
1       4             5
2       5             6

这是我的表结构，我希望在php中显示每个组联系人及其父联系人。例如。当查看组5朋友时，我想获得groupId 5及其父组记录的记录。当有人想要观看第6组大学时。结果应该是大学组，朋友组和个人组如果该组未与任何组关联，则仅显示该组记录。

Answer 1

您需要使用不同的别名加入GROUPS和Records两次。

试试这个：

SELECT GC.id,R1.name as parent,G1.groupName as ParentGroup,R2.name as child,G2.groupName as ChildGroup
FROM groups_connected GC FULL OUTER JOIN
     Records R1 ON GC.parent_id = R1.id FULL OUTER JOIN
     GROUPS G1 ON R1.groupId = G1.id FULL OUTER JOIN
     Records R2 ON GC.child_id = R2.id FULL OUTER JOIN
     GROUPS G2 ON R2.groupId = G2.id
 WHERE G1.id = 5 OR G2.id = 5

如何显示已连接组的所有记录

1 个答案: