用户行为日志表tb_user_log
| id | uid | artical_id | in_time | out_time | sign_cin |
| 1 | 101 | 9001 | 2021-11-01 10:00:00 | 2021-11-01 10:00:11 | 0 |
| 2 | 102 | 9001 | 2021-11-01 10:00:09 | 2021-11-01 10:00:38 | 0 |
| 3 | 103 | 9001 | 2021-11-01 10:00:28 | 2021-11-01 10:00:58 | 0 |
| 4 | 104 | 9002 | 2021-11-01 11:00:45 | 2021-11-01 11:01:11 | 0 |
| 5 | 105 | 9001 | 2021-11-01 10:00:51 | 2021-11-01 10:00:59 | 0 |
| 6 | 106 | 9002 | 2021-11-01 11:00:55 | 2021-11-01 11:01:24 | 0 |
| 7 | 107 | 9001 | 2021-11-01 10:00:01 | 2021-11-01 10:01:50 | 0 |
（uid-用户ID, artical_id-文章ID, in_time-进入时间, out_time-离开时间, sign_in-是否签到）
场景逻辑说明：artical_id-文章ID代表用户浏览的文章的ID，artical_id-文章ID为0表示用户在非文章内容页（比如App内的列表页、活动页等）。
问题：统计每篇文章同一时刻最大在看人数，如果同一时刻有进入也有离开时，先记录用户数增加再记录减少，结果按最大人数降序。
输出示例：
示例数据的输出结果如下
| artical_id | max_uv |
| 9001 | 3 |
| 9002 | 2 |
示例1
输入
DROP TABLE IF EXISTS tb_user_log;
CREATE TABLE tb_user_log (
id INT PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID',
uid INT NOT NULL COMMENT '用户ID',
artical_id INT NOT NULL COMMENT '视频ID',
in_time datetime COMMENT '进入时间',
out_time datetime COMMENT '离开时间',
sign_in TINYINT DEFAULT 0 COMMENT '是否签到'
) CHARACTER SET utf8 COLLATE utf8_bin;
INSERT INTO tb_user_log(uid, artical_id, in_time, out_time, sign_in) VALUES
(101, 9001, '2021-11-01 10:00:00', '2021-11-01 10:00:11', 0),
(102, 9001, '2021-11-01 10:00:09', '2021-11-01 10:00:38', 0),
(103, 9001, '2021-11-01 10:00:28', '2021-11-01 10:00:58', 0),
(104, 9002, '2021-11-01 11:00:45', '2021-11-01 11:01:11', 0),
(105, 9001, '2021-11-01 10:00:51', '2021-11-01 10:00:59', 0),
(106, 9002, '2021-11-01 11:00:55', '2021-11-01 11:01:24', 0),
(107, 9001, '2021-11-01 10:00:01', '2021-11-01 10:01:50', 0);输出
9001|3 9002|2
