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
    year (in_time) = 2021
    and month (in_time) = 11
    and artical_id != 0
group by
    date (in_time)
order by
    avg_view_len_sec