MySql selecting default value if there are no results?

Question

i\'m having 2 tables: members and comments. I select all members, and then join comments. But in comments I\'m selecting some SUM of points, and if user never commented, I can\'

Answer 1

MySQL has an IFNULL operator which allows you to return a value other than null if the result is null.

SELECT c.comment_id AS item_id, m.member_id AS member_id, m.avatar, 
            SUM(IFNULL(c.vote_value, 0)) AS vote_value, SUM(IFNULL(c.best, 0)) AS best, 
            SUM(IFNULL(c.vote_value, 0)) + SUM(IFNULL(c.best, 0))*10 AS total
            FROM members m
            LEFT JOIN comments c ON m.member_id = c.author_id
            GROUP BY c.author_id
            ORDER BY m.member_id DESC
            LIMIT 0, 20

As others mentioned, COALESCE does something similar (and also works in MySQL).