SELECT E1.emp_id,E1.emp_level,E3.tag AS exam_tag FROM ( SELECT emp_id,emp_level FROM emp_info WHERE emp_level < 7 ) E1 LEFT JOIN ( SELECT emp_id,exam_id ,time_to_sec(timediff(submit_time,start_time)) AS exam_time ,score ,avg(time_to_sec(timediff(submit_time,start_time))) OVER(PARTITION BY exam_id...