您可以使用下面的查询

SELECT b.book_name, a.author_name, c.cat_name
 FROM Books b
 JOIN BookAuthor ba ON b.book_id =ba.book_id
 JOIN Authors a ON a.author_id = ba.author_id
 JOIN BookCategory bc ON bc.book_id =b.book_id 
 JOIN Categories c ON bc.cat_id = c.cat_name
 WHERE b.book_id = 101 -- specify book id

你可能想要：

SELECT b.title, ba.authors, bc.categories
FROM books b LEFT  JOIN
     (SELECT ba.book_id, GROUP_CONCAT(a.name) as authors
      FROM bookauthor ba JOIN
           authors a
           ON a.auth_id = ba.auth_id
      GROUP BY ba.book_id
     ) ba
     ON b.book_id = ba.book_id LEFT JOIN
     (SELECT bc.book_id, GROUP_CONCAT(c.name) as categories
      FROM bookcategory bc JOIN
           categories c
           ON bc.cat_id = c.cat_id
      GROUP BY bc.book_id
     ) bc
     ON bc.book_id = b.book_id 
WHERE b.book_id = 101 -- specify book id 
GROUP BY b.book_id, b.title;

这是一把小提琴。
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