Vraag over sql select

$sql = "SELECT l.member_id as id,
        runescapename as name,
        (max(l.xp) - min(l.xp)) as xp
		from    (
		select u.id
		from UPDATES as u
		order by u.id desc
		limit  0,2
        ) u
		join     LEVELS l
		on l.update_id = u.id
		join        users m
		on m.id = l.member_id
		where        l.skill_id = 1
		group by    l.member_id
		order by    xp desc
		limit         0,3";

join LEVELS l

join LEVELS AS l

l.update_id = u.id

LEVELS.update_id = USERS.id

Andytjuh Bruggeman op 08/07/2015 23:03:28

Iemadn stuurde dit me toe en snap weinig van die 1.skill etc