How to limit values when using distinct

Question

PHP

  SELECT DISTINCT bk.title AS Title, bk.year AS Year, aut.authorname AS Author, cat.category AS Category
         FROM book bk 

         JOIN book_category          


        

Answer 1

  SELECT DISTINCT bk.title AS Title, bk.year AS Year, aut.autName AS Author, cat.category AS Category
     FROM book bk 

     JOIN book_category bk_cat 
     ON bk_cat.book_id = bk.bookid

     JOIN categories cat 
     ON cat.id = bk_cat.category_id


     JOIN (SELECT GROUP_CONCAT(aut.authorname) as autName FROM authors JOIN books_authors ON books_authors.author_id=authors.author_id WHERE books_authors.book_id=bk.bookid) as aut


     ORDER BY bk.title ASC