题解 | #每类视频近一个月的转发量/率#

select tag, 
sum(if_retweet) as retweet_cut, 
round(sum(if_retweet) / count(tag), 3) as retweet_rate
from tb_user_video_log uvl
left outer join tb_video_info vi
on uvl.video_id = vi.video_id
where end_time between 
date_add(
    (select max(end_time) from tb_user_video_log), 
    interval -30 day
)
and 
    (select max(end_time) from tb_user_video_log)
group by tag
order by retweet_rate desc;

我恨时间函数。总感觉写得很狗屎。