Question

mysql中有三个表。

表1：

 create table a1{
 no int primary key AUTO_INCREMENT,
 member_no int,
 channel varchar(50)
 };

表2：

create table a2(
no int primary key AUTO_INCREMENT,
member_no int, 
title varchar(100) not null,
description varchar(400),
video_name varchar(100)
);

和表3：

 create table a3(
 no int primary key AUTO_INCREMENT,
 member_no int, 
 video_name varchar(100)
);

我想选择满足相同条件的a1.channel。如何编写查询语句？

这是我到目前为止所做的：

select * from a2 a join a3 b on a.video_name=b.video_name and b.member_no=#          
     {member_no};

Answer 1

钝的表名没有帮助（a1，a2，a3）有钝的别名（a，b）不能让人理解，但也许这会有所帮助。

select * 
from a2 a 
join a3 b on on a.member_no = b.member_no and a.video_name = b.video_name 
join a1 c on a.member_no = c.member_no
where a.member_no= {member_no}
;

如何通过查询语句来选择多个表？

1 个答案: