正确的答案是如下所示，评论区很多人的代码有跑不通，注意要在day(last_day(submit_time))前面加上max！！！！，取数值最大的那一天 #方法一 # SELECT # coalesce(DATE_FORMAT(submit_time,"%Y%m"),'2021汇总') submit_month, # COUNT(submit_time) month_q_cnt, # round(COUNT(submit_time) / MAX(DAY(last_day(submit_time))),3)avg_day_q_cnt # FROM # practice_record # WHER...