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Test Data

-- 创建 user_activity 表
DROP TABLE IF EXISTS user_activity ;
CREATE TABLE user_activity (
    user_id STRING,
    activity_start TIMESTAMP,
    activity_end TIMESTAMP
);

-- 插入数据
INSERT INTO user_activity VALUES
('user1', '2024-07-11 08:00:00', '2024-07-11 09:00:00'),
('user2', '2024-07-11 08:30:00', '2024-07-11 09:30:00'),
('user3', '2024-07-11 09:00:00', '2024-07-11 10:00:00'),
('user4', '2024-07-11 09:15:00', '2024-07-11 09:45:00'),
('user5', '2024-07-11 09:30:00', '2024-07-11 10:30:00'),
('user6', '2024-07-11 10:00:00', '2024-07-11 11:00:00'),
('user7', '2024-07-11 08:05:00', '2024-07-11 08:55:00'),
('user8', '2024-07-11 08:45:00', '2024-07-11 09:15:00'),
('user9', '2024-07-11 09:05:00', '2024-07-11 10:05:00'),
('user10', '2024-07-11 09:25:00', '2024-07-11 10:25:00'),
('user11', '2024-07-11 08:10:00', '2024-07-11 09:10:00'),
('user12', '2024-07-11 08:20:00', '2024-07-11 09:20:00'),
('user13', '2024-07-11 08:35:00', '2024-07-11 09:35:00'),
('user14', '2024-07-11 08:50:00', '2024-07-11 09:50:00'),
('user15', '2024-07-11 09:10:00', '2024-07-11 10:10:00'),
('user16', '2024-07-11 09:20:00', '2024-07-11 10:20:00'),
('user17', '2024-07-11 09:40:00', '2024-07-11 10:40:00'),
('user18', '2024-07-11 10:05:00', '2024-07-11 11:05:00'),
('user19', '2024-07-11 10:15:00', '2024-07-11 11:15:00'),
('user20', '2024-07-11 10:25:00', '2024-07-11 11:25:00');
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De necessitates

Apicem numerum online hominum in quaque parte temporis certa ratione.

Exemplum proventuum:

Effectus torcular activity_time Ascendens.

in:

• activity_time Tempus indicat punctum statisticum;
• max_users Summum cacumen numerus hominum tunc indicat punctum.

Requisita realization

select
    date_format(activity_time,'yyyy-MM-dd HH') activity_time,
    max(total_users) max_users
from
    (select
        activity_time,
        sum(flag) over(order by activity_time) total_users
    from
        (select
            activity_start activity_time,
            1 flag
        from
            user_activity
        union all
        select
            activity_end activity_time,
            -1 flag
        from
            user_activity)t1
    )t2
group by
    date_format(activity_time,'yyyy-MM-dd HH');
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Output talis est:

Core huius quaestionis est subquery t2 Dialectica in:

	select
        activity_time,
        sum(flag) over(order by activity_time) total_users
    from
        (select
            activity_start activity_time,
            1 flag
        from
            user_activity
        union all
        select
            activity_end activity_time,
            -1 flag
        from
            user_activity)t1;
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Primo, subj t1 Columnas ad ordines converte, cur hoc facere debes? Scilicet hoc est ad actuariorum commodum.

Cogitemus de hoc. +1e contra, cum exit utentis, num multitudo augebitur? -1。

Quando login et concludere tempora in eadem columna ponimus, et per tempus, num accurate computare numerum hominum in singulis momentis? t2 Quod agimus calculos cumulativos per fenestras facere functiones;t2 Eventus similis est:

2024-07-11 08:00:00     1
2024-07-11 08:05:00     2
2024-07-11 08:10:00     3
2024-07-11 08:20:00     4
2024-07-11 08:30:00     5
2024-07-11 08:35:00     6
2024-07-11 08:45:00     7
2024-07-11 08:50:00     8
2024-07-11 08:55:00     7
2024-07-11 09:00:00     7
2024-07-11 09:00:00     7
2024-07-11 09:05:00     8
2024-07-11 09:10:00     8
2024-07-11 09:10:00     8
2024-07-11 09:15:00     8
2024-07-11 09:15:00     8
2024-07-11 09:20:00     8
2024-07-11 09:20:00     8
2024-07-11 09:25:00     9
2024-07-11 09:30:00     9
2024-07-11 09:30:00     9
2024-07-11 09:35:00     8
2024-07-11 09:40:00     9
2024-07-11 09:45:00     8
2024-07-11 09:50:00     7
2024-07-11 10:00:00     7
2024-07-11 10:00:00     7
2024-07-11 10:05:00     7
2024-07-11 10:05:00     7
2024-07-11 10:10:00     6
2024-07-11 10:15:00     7
2024-07-11 10:20:00     6
2024-07-11 10:25:00     6
2024-07-11 10:25:00     6
2024-07-11 10:30:00     5
2024-07-11 10:40:00     4
2024-07-11 11:00:00     3
2024-07-11 11:05:00     2
2024-07-11 11:15:00     1
2024-07-11 11:25:00     0
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Coetus denique et aggregatum per puncta temporis, per max Munus maximum numerum invenit apicem punctum singulis temporibus complet~