用if函数来判断是否完成
select a.video_id,round(sum(if(timestampdiff(second,start_time,end_time)>=duration,1,0))/count(start_time),3) as rate from tb_user_video_log a left join tb_video_info b on a.video_id=b.video_id where year(start_time)='2021' group by a.video_id order by rate desc;