select count(u.user_id) as n_users, to_char(max(creation_date), 'YYYY-MM-DD HH24:MI:SS') as last_registration, to_char(max(u.last_visit), 'YYYY-MM-DD HH24:MI:SS') as last_visit, sum(u.n_sessions) as total_visits from users u, acs_objects o where o.object_id = u.user_id and user_id <> 0 select count (*) from dotlrn_communities h, dotlrn_clubs c where h.parent_community_id is not null or c.club_id = h.community_id select count (*) from dotlrn_classes, dotlrn_communities_full where dotlrn_communities_full.community_type = dotlrn_classes.class_key select count (distinct acs_rels.object_id_two) from acs_rels, dotlrn_users where acs_rels.rel_type in ('[join $rels "\', \'"]') and dotlrn_users.user_id=acs_rels.object_id_two