各个视频的平均完播率

id	uid	video_id	start_time	end_time	if_follow	if_like	if_retweet	comment_id
1	101	2001	2021-10-01 10:00:00	2021-10-01 10:00:30	0	1	1	NULL
2	102	2001	2021-10-01 10:00:00	2021-10-01 10:00:24	0	0	1	NULL
3	103	2001	2021-10-01 11:00:00	2021-10-01 11:00:34	0	1	0	1732526
4	101	2002	2021-09-01 10:00:00	2021-9-01 10:00:42	1	0	1	NULL
5	102	2002	2021-10-01 11:00:00	2021-10-01 10:00:30	1	0	1	NULL

（uid-用户ID, video_id-视频ID, start_time-开始观看时间, end_time-结束观看时间, if_follow-是否关注, if_like-是否点赞, if_retweet-是否转发, comment_id-评论ID）

短视频信息表tb_video_info

id	video_id	author	tag	duration	release_time
1	2001	901	影视	30	2021-01-01 07:00:00
2	2002	901	美食	60	2021-01-01 07:00:00
3	2003	902	旅游	90	2021-01-01 07:00:00

（video_id-视频ID, author-创作者ID, tag-类别标签, duration-视频时长（秒）, release_time-发布时间）

问题：计算2021年里有播放记录的每个视频的完播率(结果保留三位小数)，并按完播率降序排序

注：视频完播率是指完成播放次数占总播放次数的比例。简单起见，结束观看时间与开始播放时间的差>=视频时长时，视为完成播放。

输出示例：

示例数据的结果如下：

video_id	avg_comp_play_rate
2001	0.667
2002	0.000

解释：

视频2001在2021年10月有3次播放记录，观看时长分别为30秒、24秒、34秒，视频时长30秒，因此有两次是被认为完成播放了的，故完播率为0.667；

视频2002在2021年9月和10月共2次播放记录，观看时长分别为42秒、30秒，视频时长60秒，故完播率为0.000。

示例1

输入:

DROP TABLE IF EXISTS tb_user_video_log, tb_video_info;
CREATE TABLE tb_user_video_log (
    id INT PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID',
    uid INT NOT NULL COMMENT '用户ID',
    video_id INT NOT NULL COMMENT '视频ID',
    start_time datetime COMMENT '开始观看时间',
    end_time datetime COMMENT '结束观看时间',
    if_follow TINYINT COMMENT '是否关注',
    if_like TINYINT COMMENT '是否点赞',
    if_retweet TINYINT COMMENT '是否转发',
    comment_id INT COMMENT '评论ID'
) CHARACTER SET utf8 COLLATE utf8_bin;

CREATE TABLE tb_video_info (
    id INT PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID',
    video_id INT UNIQUE NOT NULL COMMENT '视频ID',
    author INT NOT NULL COMMENT '创作者ID',
    tag VARCHAR(16) NOT NULL COMMENT '类别标签',
    duration INT NOT NULL COMMENT '视频时长(秒数)',
    release_time datetime NOT NULL COMMENT '发布时间'
)CHARACTER SET utf8 COLLATE utf8_bin;

INSERT INTO tb_user_video_log(uid, video_id, start_time, end_time, if_follow, if_like, if_retweet, comment_id) VALUES
  (101, 2001, '2021-10-01 10:00:00', '2021-10-01 10:00:30', 0, 1, 1, null),
  (102, 2001, '2021-10-01 10:00:00', '2021-10-01 10:00:24', 0, 0, 1, null),
  (103, 2001, '2021-10-01 11:00:00', '2021-10-01 11:00:34', 0, 1, 0, 1732526),
  (101, 2002, '2021-09-01 10:00:00', '2021-09-01 10:00:42', 1, 0, 1, null),
  (102, 2002, '2021-10-01 11:00:00', '2021-10-01 11:00:30', 1, 0, 1, null);

INSERT INTO tb_video_info(video_id, author, tag, duration, release_time) VALUES
  (2001, 901, '影视', 30, '2021-01-01 7:00:00'),
  (2002, 901, '美食', 60, '2021-01-01 7:00:00'),
  (2003, 902, '旅游', 90, '2021-01-01 7:00:00');

输出:

2001|0.667
2002|0.000

原站题解

上次编辑到这里，代码来自缓存点击恢复默认模板

Mysql 解法, 执行用时: 36ms, 内存消耗: 6380KB, 提交时间: 2021-12-27

select a.video_id,
round(sum(case when timestampdiff(second,b.start_time,b.end_time)>=a.duration then 1 else 0 end)/count(b.uid),3)
as avg_com_play_rate
from tb_video_info a join tb_user_video_log b on a.video_id=b.video_id
where YEAR(b.start_time) = 2021
group by a.video_id
order by avg_com_play_rate desc

Mysql 解法, 执行用时: 36ms, 内存消耗: 6388KB, 提交时间: 2022-01-25

select a.video_id,
round(avg(if(timestampdiff(second,start_time,end_time)>=duration,1,0)),3) as avg_comp_play_rate
from tb_user_video_log a
left join tb_video_info b
on a.video_id = b.video_id
where year(start_time)=2021
group by a.video_id
order by avg_comp_play_rate DESC;

Mysql 解法, 执行用时: 36ms, 内存消耗: 6388KB, 提交时间: 2021-12-14

select log.video_id,
round(sum(if(TIMESTAMPDIFF(second,log.start_time,log.end_time)
             >=info.duration,1,0))/count(log.video_id) ,3)
as avg_comp_play_rate
from tb_user_video_log  as log inner join tb_video_info as info
on log.video_id=info.video_id
where year(log.start_time)=2021
group by video_id 
order by avg_comp_play_rate desc

Mysql 解法, 执行用时: 36ms, 内存消耗: 6392KB, 提交时间: 2021-12-14

select t1.video_id,
    round(avg(if(TIMESTAMPDIFF(second, start_time, end_time) >= t2.duration, 1, 0)),3) avg_comp_play_rate
from tb_user_video_log t1
join tb_video_info t2 on t1.video_id = t2.video_id
where YEAR(start_time) = 2021
group by t1.video_id
order by avg_comp_play_rate desc

Mysql 解法, 执行用时: 36ms, 内存消耗: 6392KB, 提交时间: 2021-12-12

SELECT a.video_id, 
round(sum(if((end_time-start_time-b.duration) >=0,1,0))/count(a.video_id),3) avg_comp_play_rate
FROM tb_user_video_log a
left join tb_video_info b
on a.video_id = b.video_id
where year(start_time) = 2021
GROUP BY a.video_id
order by avg_comp_play_rate desc

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