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 date_format(submit_time,'%Y%m') as submit_month, any_value(count(submit_time)) as month_q_cnt, any_value(round(count(submit_time)/day(last_day(submit_time)),3)) as avg_day_q_cnt from practice_record where year(submit_time)=2021 group by date_format(submit_time,'%Y%m') union all select '2021汇总' as submit_month , any_value(count(submit_time)) as month_q_cnt,any_value(round(count(submit_time)/31,3)) as avg_day_q_cnt from practice_record where score is not null and year(submit_time)=2021 order by submit_month
求一个月有多少天:day(last_day())
select检索group by list 之外的列需要加 any_value()