题解 | #每篇文章同一时刻最大在看人数#

with
t1 as ((select artical_id,in_time dt,1 diff from tb_user_log where artical_id!=0) union all (select artical_id,out_time dt,-1 diff from tb_user_log where artical_id!=0)),
t2 as (select artical_id,sum(diff) over(partition by artical_id order by dt,diff desc ) cur_uv from t1)
select artical_id,max(cur_uv) max_uv from t2 group by artical_id order by max_uv desc