select emp_id, emp_level, tag as exam_tag from( select emp_id, emp_level, tag, exam_id, timestampdiff(second,start_time,submit_time) as time1, score from exam_record join examination_info using (exam_id) join emp_info using(emp_id) ) as ub1 join ( select tag, avg(timestampdiff(second,start_time,subm...