[SOLVED] How to join two rows in sql

Question

This is my sql code
SELECT b.book_id, concat(`first_name`, ' ', a.`last_name`) AS 'author_name', b.title
FROM
`book_authors` ba JOIN `books` b ON ba.`book_id` = b.`book_id`
JOIN `authors` a ON ba.`author_id` = a.`author_id`
WHERE
b.`book_id` > 0 IN (SELECT c.`book_id`
FROM `book_authors` c
GROUP BY c.`book_id`)
But as you can see in this screenshot below, rows with the same book_id are printed seperately. How can I 'join' them. So that the author field will be comma-seperated or sonething like that
https://www.dropbox.com/s/qsicouqkjn22u0t/Capture-1.PNG?dl=0

Answer 1

I discovered the group_concat() function in mysql is what i needed