连接3个表php / sql时出错

Question

I'm new to this, so I know I'm missing something simple, but I can't figure it out. I'm trying to join 3 tables together and I've got it working with 2 joins, but when combined in the same query, there ends up being an error.

My 3 tables are:

TBL_Authors

Author_ID
Author_Name

TBL_Publishers

Publisher_ID
Publisher_Name

TBL_Books

Title
Author_ID
Publisher_ID
ISBN
Genre
Price
Cost
Rating

What I have that isn't working:

    $query = 'SELECT * FROM TBL_PUBLISHERS
              JOIN TBL_BOOKS ON TBL_PUBLISHERS.Publisher_ID = TBL_BOOKS.Publisher_ID

              SELECT * FROM TBL_AUTHORS
              JOIN TBL_BOOKS ON TBL_AUTHORS.Author_ID = TBL_BOOKS.Author_ID

              ORDER BY TBL_BOOKS.Title ASC;';

Answer 1

This query assumes that each book was published.

SELECT 
   * 
FROM 
   TBL_Books b
   INNER JOIN TBL_Publishers p ON b.Publisher_ID = p.Publisher_ID
   INNER JOIN TBL_Authors a ON b.Author_ID = a.Author_ID 
ORDER BY 
   b.Title

Book will always have an Author, but not necessarily a Publisher, if it's not published. If you need to fetch all the books irrespective of whether published or not, you will have to change INNER join on TBL_Publishers to LEFT .

Answer 2

This Query Will show you the result of all details of book, publisher name, author name.

SELECT 
t1.* , t2.Publisher_Name , t3.Author_Name 
FROM 
TBL_Books as t1 
INNER JOIN TBL_Publishers as t2 ON t1.Publisher_ID = t2.Publisher_ID
INNER JOIN TBL_Authors as t3 ON t1.Author_ID = t2.Author_ID 
ORDER BY 
t1.Title

Check This and update if this query helps you.