SELECT IFNULL(t1,'2021汇总') AS submit_month,month_q_cnt,avg_day_q_cntFROM (SELECT DATE_FORMAT(submit_time,'%Y%m') AS t1,COUNT(*) AS month_q_cnt,ROUND(COUNT(*)/MAX(DAY(LAST_DAY(submit_time))),3) AS avg_day_q_cntFROM practice_recordWHERE ...