我写的是一个三层select语句,第一层选出需要的数据: select uid, tl.video_id, tag, duration, timestampdiff(second,start_time,end_time) as duration_a, if((timestampdiff(second,start_time,end_time))>duration, 1, ((timestampdiff(second,start_time,end_time))/duration)) as play_progress from tb_user_vide...