如何使用查詢語句來選擇多個表？

Question

mysql中有三個表。

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) 
); 

我想選擇滿足相同條件的a1.channel。 如何編寫查詢語句？

這是我到目前爲止有：

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

Answer 1

鈍表名不幫忙（A1，A2，A3）與鈍別名（A，B）不要讓偉大的理解，但也許這會有所幫助。

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} 
;