题解 | #月总刷题数和日均刷题数#

select date_format(submit_time,"%Y%m") submit_month,
        round(count(submit_time),3) month_q_cnt,
        any_value(round(count(submit_time)/day(LAST_DAY(submit_time)),3)) avg_day_q_cnt
    from practice_record
    where year(submit_time)='2021'
    group by submit_month

union all
select concat(year(submit_time),'汇总') submit_month,
        round(count(submit_time),3) month_q_cnt,
        round(count(submit_time)/31,3) avg_day_q_cnt
    from practice_record
    where year(submit_time)='2021'
    group by submit_month
    order by submit_month ;
	这题目还是挺难的