Mysql COUNT(*) on multiple tables

Question

What\'s wrong with this query:

SELECT co.*, mod.COUNT(*) as moduleCount, vid.COUNT(*) as vidCount 
 FROM courses as co, modules as mod, videos as vid 
 WHERE         


        

Answer 1

SELECT co.*, m.ModCnt as moduleCount, v.VidCnt as vidCount 
FROM courses co
INNER JOIN (
        select count(*) AS ModCnt, co.id AS CoID
        from modules 
        group by co) m
    ON m.CoID = co.id
INNER JOIN (
        select count(*) AS VidCnt, co.id AS CoID
        from videos
        group by co) v
    ON v.CoID = co.id   
INNER JOIN videos vid 
    ON vid.course_id = co.id 
ORDER BY co.id DESC