题解 | #2021年11月每天的人均浏览文章时长#

select 
    date(in_time) as dt,
    round(sum(timestampdiff(second,in_time,out_time))
    /count(distinct uid),1) 
    as avg_view_len_sec
from 
    tb_user_log
where
    artical_id != '0' and year(in_time) = '2021' and month(in_time) = '11'
group by 
    date(in_time)
order by
    avg_view_len_sec;