上面这题想请问一下,求平均进度大于60%的视频

SELECT T2.tag,
CONCAT(ROUND(AVG(IF(TIMESTAMPDIFF(SECOND,start_time,end_time)>=duration,1,
                    TIMESTAMPDIFF(SECOND,start_time,end_time)/duration
                   ))*100,2),"%")
AS avg_play_progress
FROM tb_user_video_log AS T1
LEFT JOIN tb_video_info AS T2
ON T1.video_id=T2.video_id
GROUP BY tag
HAVING REPLACE(avg_play_progress,'%','') > 60
ORDER BY avg_play_progress desc

为什么要用 ON T1.video_id=T2.video_id ，where就没法运行