-- 左连接两个表 -- 把二表的时间附上来 select p2.video_id, -- 这一步是关键 计算各个视频的完播率 round(sum(if((p2.watch_time-p2.duration) >=0,1,0))/count(p2.video_id),3) avg_comp_play_rate -- count(p2.watch_time>=p2.duration) avg_comp_play_rate from (SELECT uid, video_id, end_time-start_time watch_time, duration -- 表1...