SELECT
er.emp_id,
emp.emp_level,
t1.tag exam_tag
FROM
(SELECT
ei.exam_id,
ei.tag ,
AVG(er.score) avg_score,
AVG(TIMESTAMPDIFF(MINUTE, er.start_time, er.submit_time)) avg_time
FROM exam_record er
JOIN examination_info ei ON ei.exam_id = er.exam_id
GROUP BY ei.exam_id, ei.tag) t1
JOIN exam_record er ON er.exam_id = t1.exam_id
JOIN emp_info emp ON emp.emp_id = er.emp_id
WHERE er.score > avg_score AND TIMESTAMPDIFF(MINUTE, er.start_time, er.submit_time) < avg_time AND emp_level < 7
ORDER BY er.emp_id, t1.exam_id