题解 | #月总刷题数和日均刷题数#

select date_format(submit_time,'%Y%m') submit_month,count(*) month_q_cnt,round(count(*)/any_value(day(last_day(submit_time))),3) avg_day_q_cnt
from practice_record
where year(submit_time)=2021
group by submit_month
union 
select '2021汇总',count(*),round(count(*)/any_value(day(last_day(submit_time))),3) avg_day_q_cnt
from practice_record
where year(submit_time)=2021
order by submit_month;