select author, month, round((addfans)/cnt,3) as fans_growth_rate, sum(addfans) over(partition by author order by author,month) as total_fans from( select date_format(start_time,'%Y%-%m') as month, sum(if(if_follow=2,-1,if_follow)) as addfans,author, count(*) as cnt from tb_user_video_log join tb_video_info using(video_id) group by author,month )a where month >='2020-12' order by author,total_fans