用于连接表的SQL查询

Question

我有一个像这样的order表

id  | bookId | bookAuthorId
--------------------------
1      3         2      
2      2         1        
3      1         2        

和另一张表

bookId  |  book
---------------
  1       bookA
  2       bookB
  3       bookC

和

bookAuthorId  |  author
------------------------
  1              authorA
  2              authorB

我想从order表格获取记录，其中id = 1结果集如此

id | book | author

我尝试了什么：

select * from order 
join bookId,bookAuthorId 
   on order.bookId = books.bookId 
       and order.authorId = authors.authorId

我不知道如何加入这些表来获得所需的结果。我该怎么做？

Answer 1

select o.id, b.book, a.author
from 'order' o
join book b on o.bookid=b.bookid
join author a on o.bookauthorid=a.bookauthorid 
where o.id=1

Answer 2

您可以使用where子句

来执行此操作

select 
    id, book, author 
from 
    `order`, book, author 
where 
    `order`.bookId = book.bookId 
    and 
    `order`.authorId = author.authorId

---

或者

select 
    o.id, b.book, a.author
from 
    `order` o 
natural join
    book b
natural join
    author a

Answer 3

select `order`.id, book.book, author.author
from `order`
join book on (`order`.bookId = book.bookId)
join author on (author.bookAuthorId = book.bookId)
where `order`.id = 1;

假设bookAuthorId可以链接到bookId，否则你需要添加一个外键。