题解 | #每篇文章同一时刻最大在看人数# 无窗口函数

with cte as(select t1.artical_id, count(t2.in_time) + 1 as uv
from tb_user_log t1 join tb_user_log t2 
on t1.artical_id = t2.artical_id and t1.out_time >= t2.in_time and t1.out_time < t2.out_time
where t1.artical_id != 0
group by 1,t1.in_time)

select artical_id, max(uv) as max_uv
from cte
group by 1
order by 2 desc

利用join连接计算每个文章的每个阅读记录的与之同时的记录（即有时间交叉）