统计视频观看数Top10

• 思路：使用order by按照 views 字段做一个全局排序，设置只显示前10条即可
  实现SQL：

select videoid,uploader,age,category,length,views,rate,ratings,comments
from guliyingyin_video_orc
order by views desc
limit 10;

![在这里插入图片描述](https://img-blog.csdnimg.cn/20200222225830179.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpYW5naGVjYWk1MjE3MTMxNA==,size_16,color_FFFFFF,t_70)

• 结果：
  

统计视频类别热度Top10

思路：炸开数组”视频类别“字段，然后按照类别分组，最后按照热度(视频个数)排序。

因为当前表结构为：一个视频对应一个或多个类别。所以如果要 group by 类别，需要先将类别进行列转行(展开)，然后再进行count即可

• 分析过程：

1. 炸开类别，记为临时表t1

   select videoId,catName
   from guliyingyin_video_orc
   lateral view explode(category) tb_category as catName; — t1

2. 按照类别 group by 聚合，然后count组内的videoId个数，记为临时表t2

   select catName,count(*) hot
   from t1
   group by catName; —t2

3. 最后按照热度排序，显示前10条。

   select catName, hot
   from t2
   order by hot desc
   limit 10;

• 完整的SQL：

  SELECT
  	catName,
  	hot 
  FROM
  	(
  	SELECT
  		catName,
  		count( * ) hot 
  	FROM
  		( SELECT videoId, catName FROM guliyingyin_video_orc lateral VIEW explode ( category ) tb_category AS catName ) t1 
  	GROUP BY
  		catName 
  	) t2 
  ORDER BY
  	hot DESC 
  	LIMIT 10;
  

将完整的SQL语句保存到guliyingying.sql文件中，并上传到Linux。然后执行命令：

结果：

统计视频观看数Top20所属类别

• 思路：

1. 先找到观看数最高的20个视频，记为临时表t1

   select videoid,views,category
   from guliyingyin_video_orc
   order by views desc
   limit 20; ----t1

2. 把这20条信息中的category分裂出来(列转行)，记为临时表t2

   select videoid,catName
   from t1
   lateral view explode(category) tb_category as catName; — t2

3. 去重

   select distinct catName
   from t2;

• 完整SQL

SELECT DISTINCT
	catName 
FROM
	(
	SELECT
		videoid,
		catName 
	FROM
	( SELECT videoid, views, category FROM guliyingyin_video_orc ORDER BY views DESC LIMIT 20 ) t1 lateral VIEW explode ( category ) tb2_category AS catName 
	) t2;

将完整的SQL语句保存到guliyingying.sql文件中，并上传到Linux。然后执行命令：

结果：

统计视频观看数Top50所关联视频的类别的Rank

思路分析：

思路：

1. 查询出观看数最多的前50个视频的所有信息(包含每个视频对应的关联视频)，记为临时表t1

   select videoId, views, category, relatedId
   from guliyingyin_video_orc
   order by views desc
   limit 50; ----t1

2. 炸裂关联视频id：将找到的50条视频信息的相关视频的relatedId列转行，记为临时表t2

   select distinct videoId_name
   from t1
   lateral view explode(relatedId) tb_relatedId as videoId_name; ----t2

3. 将关联视频的id和guliyingyin_video_orc表进行inner join操作，得到每个关联视频id的详细数据，记为临时表t4

   select *
   from t2
   inner join guliyingyin_video_orc t3
   on t2.videoId_name=t3.videoId; ---- t4

4. 炸裂关联视频的类别

   select *
   from t4
   lateral view explode(category) tb_category as catName; ----t5

5. 统计类别个数

   select catName, count(*) hot
   from t5
   group by catName; ----t6

6. 统计类别的热度排名

   select *
   from t6
   order by hot desc;

• 完整SQL：

SELECT
	* 
FROM
	(
	SELECT
		catName,
		count( * ) hot 
	FROM
		(
		SELECT
			* 
		FROM
			(
			SELECT
				* 
			FROM
				(
				SELECT DISTINCT
					videoId_name 
				FROM
					( SELECT videoId, views, category, relatedId FROM guliyingyin_video_orc ORDER BY views DESC LIMIT 50 ) t1 lateral VIEW explode ( relatedId ) tb_relatedId AS videoId_name 
				) t2
				INNER JOIN guliyingyin_video_orc t3 ON t2.videoId_name = t3.videoId 
			) t4 lateral VIEW explode ( category ) tb_category AS catName 
		) t5 
	GROUP BY
		catName 
	) t6 
ORDER BY
	hot DESC;

将完整的SQL语句保存到guliyingying.sql文件中，并上传到Linux。然后执行命令：

结果：

统计每个类别中的视频热度Top10，以Music为例

思路：要想统计Music类别中的视频热度Top10，需要先找到Music类别，那么就需要将category炸开。

1. 创建一个临时表用于存放categoryId炸开的数据

   create table guliyingyin_category_orc(
   videoId string, 
   uploader string, 
   age int, 
   categoryId string, 
   length int, 
   views int, 
   rate float, 
   ratings int, 
   comments int,
   relatedId array
   )
   row format delimited 
   fields terminated by "\t"
   collection items terminated by "&"
   stored as orc;
   

2. 向category展开的表中插入数据。

   insert overwrite table guliyingyin_category_orc
   select  videoid,uploader,age,categoryId,length,views,rate,ratings,comments,relatedId
   from guliyingyin_video_orc
   lateral view explode(category) tb_category as categoryId;
   

3. 统计对应类别（Music）中的视频热度。

   select  videoId,views
   from guliyingyin_category_orc
   where categoryId = "Music"
   order by views desc
   limit 10;
   

   
   结果：
   

统计每个类别中视频流量Top10，以Music为例

select  videoId,ratings
from guliyingyin_category_orc
where categoryId = "Music"
order by ratings desc
limit 10;

结果：

统计上传视频最多的用户Top10以及他们上传的观看次数在前20的视频

• 分析

1. 上传视频最多的用户Top10，记为表t1

   select uploader
   from guliyingyin_user_orc
   order by videos desc
   limit 10; -----t1
   

2. 观看次数在前20的视频

   select t1.uploader,t2.videoId,views
   from t1 inner join guliyingyin_video_orc t2
   on t1.uploader= t2.uploader 
   order by views desc
   limit 20;
   

• 完整SQL语句

SELECT
	t1.uploader,
	t2.videoId,
	views 
FROM
	( SELECT uploader FROM guliyingyin_user_orc ORDER BY videos DESC LIMIT 10 ) t1
	INNER JOIN guliyingyin_video_orc t2 ON t1.uploader = t2.uploader 
ORDER BY
	views DESC 
	LIMIT 20;

• 结果
  

统计每个类别视频观看数Top10

• 思路：

1. 先得到categoryId展开的中间表

2. 子查询按照categoryId进行分区，然后分区内排序，并生成递增数字，该递增数字这一列起名为rank列

   select videoid,categoryid,views,
   row_number() over(partition by categoryid order by views desc) rank234
   from guliyingyin_category_orc;
   

3. 通过子查询产生的临时表，查询rank值小于等于10的数据行即可

   select * 
   from t1
   where rank