题目:各个视频的平均完播率
sql
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 10:00:21', 0, 0, 1, null),
(103, 2001, '2021-10-01 11:00:50', '2021-10-01 11:01:20', 0, 1, 0, 1732526),
(102, 2002, '2021-10-01 11:00:00', '2021-10-01 11:00:30', 1, 0, 1, null),
(103, 2002, '2021-10-01 10:59:05', '2021-10-01 11:00:05', 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, '2020-01-01 7:00:00');
答案
sql
select
t1.video_id ,
round(count(if(t1.end_time-t1.start_time >= duration, 1, null)) / count(*),3)
as avg_comp_play_rate
from
tb_user_video_log t1
join tb_video_info t2
on
t1.video_id = t2.video_id
where
substring(t1.start_time, 1, 4) = '2021'
group by
t1.video_id
order by avg_comp_play_rate desc