連接四個表

Question

我有三個表，我想知道是否應該加入，這些表的結構如下：

members                                                          

member_id    login    


permissions

K_id    member_id   date


kcontent

K_id    id    content  


ktitle

K_id          title

我想做的是，對於特定成員（member_id）....獲取每個成員鏈接到的每個K_id，按日期DESC對其進行排序，然后從kcontent中獲取內容，該內容由id和title從標題

Answer 1

是的你應該。

嘗試以下方法：

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