MySQL MySQL三重连接
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MySQL triple join
提问by Biker John
Im having a hard time building the triple join query.
我很难构建三重连接查询。
I have three tables:
我有三张表：
House:
房子：
house ID(key) | Address | personID |
Person:
人：
personID (key) | Name | Address |
Images:// of house
图片：//房子
imageID (key) | personID | url |
I would like to limit the results to 5.
我想将结果限制为5。
I want to query house address-es (main), it's owner name & address, and one picture of the owner.
我想查询房屋地址-es（主要），它的所有者姓名和地址，以及所有者的一张照片。
Note: There are up to 3 images of every person (3 rows in image table), but just one is necessary, doesnt matter which one.
注意：每个人最多有 3 张图像（图像表中的 3 行），但只需要一张，不管是哪一张。
回答by TheHe
SELECT h.Address, p.Name, p.Address as OwnerAddress, i.url FROM house AS h
INNER JOIN person AS p ON p.personID = h.personID
INNER JOIN images AS i ON i.personID = p.personID
GROUP BY h.houseID
should work for you.
应该为你工作。
回答by leonardo_assumpcao
Maybe it'd better for you to use LEFT OUTER JOIN, something like
也许你最好使用 LEFT OUTER JOIN，比如
SELECT
h.Address as `h_address`,
p.Name as `p_name`,
p.Address as `p_address`,
i.url as `i_url`
FROM house AS `h`
LEFT OUTER JOIN person AS `p` ON (p.personID = h.personID)
LEFT OUTER JOIN images AS `i` ON (p.personID = i.personID)
GROUP BY h.houseID
It would display also houses with no registered images.
它还会显示没有注册图像的房屋。
回答by Sabir Hussain
joining three tables
连接三个表
i.e:
IE：
select i_f.*, i_f_d.* , i_f_c.creator_name
from indent_form i_f
join indent_form_details i_f_d on i_f.id=i_f_d.ind_id
join indent_form_creator i_f_c on i_f.user_id=i_f_c.id
indent_form table 1,
indent_form_details table 2,
indent_form_creator table 3,
