如何描述要从联接表中选择的列

Question

I have 2 tables:

authors table:

id_author
author(author name in this column)

author_ind table:

id_book
id_author

My query is:

      SELECT author
        FROM authors
   LEFT JOIN author_ind 
          ON author_ind.id_book = author_ind.id_author
   LEFT JOIN authors author 
          ON author_ind.id_author = authors.id_author
       WHERE author_ind.id_book=%d

I need to get the authors info from the authors table based on the id_book from the author_ind table. MYSQL error #1052 - Column 'author' in field list is ambiguous.

Little help please:)

Update: thank you everyone. correct query:

SELECT authors.author
  FROM authors, author_ind
 WHERE author_ind.id_book =14
   AND authors.id_author = author_ind.id_author

14 is just a book id, I used it to test if it worked instead of %d

Answer 1

Based on what you're trying to get, you've made this more complex than it needs to be. You don't need to do a 2nd join on the authors table. Also, if you only want authors who have a record in the author_ind table, you can do a INNER JOIN instead of LEFT JOIN :

SELECT author
FROM authors
INNER JOIN author_ind 
      ON authors.id_author = author_ind.id_author
WHERE author_ind.id_book=%d