MySQL: Not unique table/alias: 'favourites'

Question

Hello folks.

The error I'm getting is:

Not unique table/alias: 'favourites'

I apologise for the reasonably intense query(!):

    SELECT code.id AS codeid, code.featured AS featured, code.title AS codetitle, code.summary AS codesummary, code.author AS codeauthor, code.date, code.challengeid,
    ratingItems.*, FORMAT((ratingItems.totalPoints / ratingItems.totalVotes), 1) AS rating,
    code_tags.*, tags.*,
    users.firstname AS authorname, users.id AS authorid,
    GROUP_CONCAT(tags.tag SEPARATOR ', ') AS taggroup,
    COUNT(DISTINCT comments.codeid) AS commentcount,
    favourites.id, favourites.code_id, favourites.user_id

    FROM (code)
    JOIN code_tags ON code_tags.code_id = code.id
    JOIN tags ON tags.id = code_tags.tag_id
    JOIN users ON users.id = code.author
    LEFT JOIN comments ON comments.codeid = code.id
    LEFT JOIN ratingItems ON uniqueName = code.id
    LEFT JOIN favourites ON favourites.user_id = 10
    LEFT JOIN favourites ON favourites.code_id = code.id

    GROUP BY code_id
    ORDER BY date desc

What am I doing wrong? I really can't understand it...

Thanks!

Jack

Answer 1

I guess that you only want to join with the favourites table once but with two conditions. If so use this:

LEFT JOIN favourites ON  favourites.user_id = 10
                     AND favourites.code_id = code.id

If you do actually want to join with this table twice then you need to give it two different aliases:

LEFT JOIN favourites f1 ON f1.user_id = 10
LEFT JOIN favourites f2 ON f2.code_id = code.id

Then in the SELECT list you instead of favourites you need to use either f1 or f2 as appropriate.