题解 | #每篇文章同一时刻最大在看人数#

#统计<每篇文章><同一时刻>《最大》在看人数，如果同一时刻有进入也有离开时，先记录用户数增加再记录减少，结果按最大人数降序。
with t as 
(select t1.artical_id, sum(t1.uv) over (partition by t1.artical_id order by t1.time, t1.uv desc )as online_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 )as t1
          where artical_id<>0 
           )

select t.artical_id, max(online_uv) as max_uv
from t
group by artical_id
order by max_uv desc;