题解 | #月总刷题数和日均刷题数#
月总刷题数和日均刷题数
https://www.nowcoder.com/practice/f6b4770f453d4163acc419e3d19e6746
select extract(year_month from submit_time) submit_month, count(*) month_q_cnt, round(count(*)/avg(day(last_day(submit_time))),3) avg_day_q_cnt from practice_record where year(submit_time) = '2021' group by extract(year_month from submit_time) union select '2021汇总' as submit_month, count(*) month_q_cnt, round(count(*)/31,3) avg_day_q_cnt from practice_record where year(submit_time) = '2021' order by submit_month;