select ei.exam_id,count(distinct er.uid) as uv , round(avg(er.score),1) as avg_score from user_info as ui , examination_info as ei, exam_record as er WHERE ui.uid = er.uid and er.exam_id = ei.exam_id and DATE_format(ei.release_time, '%y-%m-%d') = DATE_format(er.submit_time, '%y-%m-%d') and ui.level > 5 and ei.tag = 'SQL' and er.submit_time is not null group by ei.exam_id order by uv desc,avg_score asc;