MySQL Query : select b.inputtime, b.url,b.title,b.thumb from camp_position_data a,camp_news b where a.id=b.id and a.posid=25 and b.inputtime between 1519833600 and 1522511999 group by ddd order by ddd DESC LIMIT 20 MySQL Error : Unknown column 'ddd' in 'group statement' MySQL Errno : 1054 Message : Unknown column 'ddd' in 'group statement' Need Help?