题解 | #2021年11月每天的人均浏览文章时长#

理解题意
1、只需要2021年11月的 where date_format(in_time,"%Y%m)=2021-11
2、每天 group by
3、人均浏览 distinct uid
4、 文章时长 article_id !=0

SELECT dt,round(sum(ti)/count(distinct uid),1)as avg_view_len_sec
from(
select date_format(in_time,"%Y-%m-%d")as dt,uid, TIMESTAMPDIFF(SECOND,in_time,out_time)as ti 
from tb_user_log
where date_format(in_time,"%Y-%m")="2021-11" and artical_id !=0)a
group by dt
order by avg_view_len_sec