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mysql - 使用 MySQL 连接三个表

转载 作者:IT老高 更新时间:2023-10-28 12:51:05 26 4
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我有三个名为

的表
**Student Table**
-------------
id name
-------------
1 ali
2 ahmed
3 john
4 king

**Course Table**
-------------
id name
-------------
1 physic
2 maths
3 computer
4 chemistry

**Bridge**
-------------
sid cid
-------------
1 1
1 2
1 3
1 4
2 1
2 2
3 3
3 4
4 1
4 2

现在显示学生姓名和他学习过的类(class)名称,

**Result**
---------------------------
Student Course
---------------------------
ahmed physic
ahmed maths
ahmed computer
ahmed chemistry
ali physic
ali maths
john computer
john chemistry
king physic
king maths

我构建以下查询

select s.name as Student, c.name as Course from student s, course c join bridge b on c.id = b.cid order by s.name

但它没有返回所需的结果...

如果我想找出谁是经理而不是其他人,那么规范化的形式是什么:

**employee**
-------------------
id name
-------------------
1 ali
2 king
3 mak
4 sam
5 jon

**manage**
--------------
mid eid
--------------
1 2
1 3
3 4
4 5

并且想要得到这个结果:

**result**
--------------------
Manager Staff
--------------------
ali king
ali mak
mak sam
sam jon

最佳答案

使用 ANSI 语法,你如何加入表格会更清楚:

SELECT s.name as Student, c.name as Course 
FROM student s
INNER JOIN bridge b ON s.id = b.sid
INNER JOIN course c ON b.cid = c.id
ORDER BY s.name

关于mysql - 使用 MySQL 连接三个表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3709560/

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