题解 | #每篇文章同一时刻最大在看人数#
每篇文章同一时刻最大在看人数
https://www.nowcoder.com/practice/fe24c93008b84e9592b35faa15755e48
#同一时间在线人数需要使用sum窗口函数统计每个视频按照时间累积的观看人数。需要先计算出每个时间段的在线人数和离开人数并合并 select artical_id ,max(uv) max_uv from ( select artical_id ,dt ,sum(diff)over(partition by artical_id order by dt,diff desc) uv#这里如果出现同一时间先记录增加再记录减少所以order by dt,diff desc from ( 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 )table1 )table2 group by 1 order by 2 desc;