题解 | #每类视频近一个月的转发量/率#

# 每类视频
# 最近一个月的转发量和转发率
# 转发率降序
select 
    info.tag tag,
    sum(log.if_retweet) retweet_cnt,
    round(sum(log.if_retweet)/count(log.uid),3) retweet_rate
from tb_user_video_log log join tb_video_info info 
    on log.video_id = info.video_id
where datediff((select start_time from tb_user_video_log order by start_time desc limit 1),log.start_time) < 30 
	and  datediff((select start_time from tb_user_video_log order by start_time desc limit 1),log.start_time)>=0
group by info.tag
order by retweet_rate desc;