牛客网SQL160

国庆期间每类视频点赞量和转发量_牛客题霸_牛客网

select *
from
(
select tag,dt,
sum(单日点赞量)over(partition by tag order by dt rows between 6 preceding and 0 following),
max(单日转发量)over(partition by tag order by dt rows between 6 preceding and 0 following)
from
(
select dt,tag,sum(if_like) 单日点赞量,sum(if_retweet) 单日转发量
from
(select id,video_id,if_like,if_retweet,date_format(start_time,'%Y-%m-%d') dtfrom tb_user_video_logwhere date_format(start_time,'%Y-%m-%d') between '2021-09-25' and '2021-10-03'
) a
join
(select video_id,tagfrom tb_video_info
) b
on a.video_id=b.video_id
group by dt,tag
) c
) d
where dt between '2021-10-01' and '2021-10-03'
order by tag desc,dt

注意点：

1. date_format中%Y和%y好像不一样 ；

2. 注意时间相关的函数，如果想当成数字取用要注意是不是带“-”的，小细节问题，如果带“-”，你和数字直接去比较肯定不一样。

比较的时候一般用between and比较多

3. 认识了mysql中三个时间相关的函数：

convert(start_time,char(10))

date_format(start_time,'%Y-%m-%d')

date(start_time)

结果都是2021-09-25的格式