select a.emp_id,emp_level,tag exam_tag from exam_record a join (select exam_id,sum(score)/count(emp_id) avgscore,sum(timestampdiff(second,start_time,submit_time))/count(emp_id) avgtime from exam_record group by exam_id) b join emp_info c join examination_info d on a.exam_id=b.exam_id and a.emp_id=c....