题解 | #2021年11月每天的人均浏览文章时长#

select
    date_format (a.in_time, '%Y-%m-%d') dt,
    round(
        sum(timestampdiff (second, a.in_time, a.out_time)) / count(distinct a.uid),
        1
    ) avg_viiew_len_sec
from
    tb_user_log a
where
    year (a.in_time) = 2021
    and month (a.in_time) = 11
    and artical_id !=0
group by
    dt
order by
    avg_viiew_len_sec