题解 | 每篇文章同一时刻最大在看人数

select
    artical_id,
    max(cnt_uv) as max_uv
from
    (
        (
            select
                artical_id,
                sum(uv) over (
                    partition by
                        artical_id
                    order by
                        time,
                        uv desc
                ) as cnt_uv
            from
                (
                    select
                        artical_id,
                        in_time as time,
                        1 as uv
                    from
                        tb_user_log
                    union all
                    select
                        artical_id,
                        out_time as time,
                        -1 as uv
                    from
                        tb_user_log
                ) a
        where artical_id !=0
        )
    ) b
group by
    artical_id
order by
    max_uv desc