with t_avg_time as ( select exam_id, avg(timestampdiff(second, start_time, submit_time)) as avg_time from exam_record group by exam_id ), t_avg_score as ( select exam_id, avg(score) as avg_score from exam_record group by exam_id ) select a.emp_id, emp_level, tag as exam_tag from ( select emp_id, exa...