题解 | #每篇文章同一时刻最大在看人数#

select artical_id,max(num_cnt) as max_uv
from
    (select artical_id,
    sum(num) over(partition by artical_id order by read_time asc,num desc) as num_cnt
    from
        (select artical_id,in_time as read_time,1 as num
        from tb_user_log
        where artical_id!=0
        union all
        select artical_id,out_time as read_time,-1 as num
        from tb_user_log
        where artical_id!=0
        ) as t1
     )as t2
group by artical_id
order by max_uv desc