连接四个表

Question

我有三个表，我想知道是否应该加入，这些表的结构如下：

members                                                          

member_id    login    


permissions

K_id    member_id   date


kcontent

K_id    id    content  


ktitle

K_id          title

我想做的是，对于特定成员（member_id）....获取每个成员链接到的每个K_id，按日期DESC对其进行排序，然后从kcontent中获取内容，该内容由id和title从标题

Answer 1

是的你应该。

尝试以下方法：

SELECT a.member_id, b.date, d.title, c.content
FROM members as a
JOIN permissions as b
ON b.member_id = a.member_id
JOIN kcontent as c
ON c.k_id = b.k_id
JOIN ktitle as d
ON d.k_id = b.k_id
WHERE a.member_id = {inputMemberId}
ORDER BY b.date, d.k_id, d.title

Answer 2

SELECT *
FROM 
PERMISSIONS INNER JOIN KCONTENT
ON PERMISSIONS.K_ID = KCONTENT.K_ID
INNER JOIN KTITLE
ON KCONTENT.K_ID = KTITLE.K_ID
INNER JOIN MEMEBRS
ON MEMBERS.MEMBER_ID = PERMISSIONS.MEMBER_ID
WHERE MEMBERS.MEMBER_ID = ###
ORDER BY PERMISSIONS.DATE, MEMBERS.MEMBER_ID