49. 视频热度问题

谨以此笔记献给浪费掉的两个小时。

此题存在多处疑点和表达错误的地方，如果你看到了这篇文章，劝你跳过该题。

该题对提升HSQL编写能力以及思维逻辑能力毫无帮助。

实现一

with info as (
    -- 将数据与 video_info 关联，取出 duration
    select t1.video_id                                           as video_id,
           -- 计算观看时长（s）
           unix_timestamp(end_time) - unix_timestamp(start_time) as view_time,
           if_like,
           if_retweet,
           comment_id,
           duration
    from video_info t1
             join
         user_video_log t2
         on t1.video_id = t2.video_id
)

select distinct video_id,
                -- 计算热度
                cast(ceil(100 * (seeding_num / video_num) + 5 * like_num + 3 * comment_num +
                          2 * retweet_num) as decimal(16, 1)) as heat
from (
         -- 计算出每个视频的热度 项
         select video_id,
                -- 新鲜度(别问我为什么)
                1                                                                  as freshness,
                -- 完播数
                sum(if(view_time = duration, 1, 0)) over (partition by video_id)   as seeding_num,
                -- 该视频播放次数
                count(1) over (partition by video_id)                              as video_num,
                -- 点赞数
                sum(if_like) over (partition by video_id)                          as like_num,
                -- 转发数
                sum(if_retweet) over (partition by video_id)                       as retweet_num,
                -- 评论数
                sum(if(comment_id is not null, 1, 0)) over (partition by video_id) as comment_num
         from info
     ) t1
order by heat desc
limit 3;
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题目来源

http://practice.atguigu.cn/#/question/49/desc?qType=SQL