Question

I’m trying to do the following MySql query and when i go to run it, it tells me that “q.object_id” in the sub-query is unknown (if i change it to o.id, it says the same).

SELECT q.*, (SELECT c.title 
             FROM api_course c 
             LEFT OUTER JOIN api_object_parents op 
                 ON c.object_id = op.parent 
                     AND op.object_id = q.object_id) as parent_title
    FROM api_quiz q
    LEFT OUTER JOIN api_object o ON q.object_id = o.id
    WHERE o.type = 'Quiz'

Basically i need to get the same id that is being used in the main query and use that in a sub-query.

Thanks!

Answer 1

is this what you are looking for?

SELECT  a.*, d.title
FROM    api_quiz a
            LEFT JOIN   api_object b
                on a.object_id = b.id
            LEFT JOIN   api_object_parents c
                ON c.parent = a.object_id
            LEFT JOIN   api_course d 
                ON c.object_id = c.parent