select t1.rc_user_text, t1.wiki, count(*) from (( select rc_user_text, 'enwiki' as 'wiki' from enwiki_p.recentchanges where rc_timestamp > '20150929000000' ) union all ( select rc_user_text, 'frwiki' as 'wiki' from frwiki_p.recentchanges where rc_timestamp > '20150929000000' ) union all ( select rc_user_text, 'commonswiki' as 'wiki' from commonswiki_p.recentchanges where rc_timestamp > '20150929000000' ) ) as t1 group by t1.rc_user_text, t1.wiki order by count(*) desc limit 50;