为此所需的 SQL 是残酷的;它会给你的优化器一个非常严肃的锻炼。
从问题和问题之后的评论来看,如果它们都落在相邻事件之间的某个固定间隔内,则希望将大表中给定用户 ID 的事件序列视为“连续的”。例如,固定间隔为 3 小时。我正在为 IBM Informix Dynamic Server 编码(为了争论,版本 11.70,但 11.50 也可以正常工作)。这意味着我需要解释一个特殊的符号。具体来说,符号3 UNITS HOUR
表示3小时的间隔;它也可以用INTERVAL(3) HOUR TO HOUR
SQL 的 Informix 方言或INTERVAL '3' HOUR
标准 SQL 编写。
生成 SQL 有几个关键技术,尤其是复杂的 SQL。一种是逐步、零碎地构建 SQL,组装最终结果。另一个是确保你清楚地说明你所追求的。
在下面的符号中,“for the same User_ID”的限定应被视为始终是表达式的一部分。
在大表中,在加入小表之前,我们要考虑三类范围。
- 既没有足够接近的事件之前的事件时间行也没有足够接近的事件之后的事件时间的行的条目。这是一个开始和结束时间相同的时间范围。
- 表中的一对条目,它们本身足够接近,但既没有事件早于足够接近的对的早期事件,也没有事件晚于足够接近的对的晚期事件,也没有事件在这对之间。
- 表中三个或更多条目的序列,其中有:
- 没有事件 E1 早于足够接近的最早事件
- 没有事件 E2 晚于足够接近的最新事件
- 晚于最早的事件 E3 与最早的足够接近
- 一个比最新事件更早的事件 E4 与最新事件足够接近(E4 可能与 E3 事件相同)
- 最早和最晚之间没有一对事件 E5、E6,其中 E5 和 E6 之间没有事件,但 E5 和 E6 之间的差距太大而无法计算。
从描述中可以看出,这将是一些可怕的 SQL!
注意:代码现在已经过测试;一些(主要是小的)改变是必要的。一项不必要的小改动是在中间查询中添加了 ORDER BY 子句。另一个不必要的更改是从小表中选择其他数据进行验证。此修订是在没有研究msh210发布的修订版本的情况下进行的。
另请注意,我不确定这是一个最小的公式;使用单个 SELECT 语句而不是三个 SELECT 语句的 UNION 对所有范围进行分类可能是可行的(如果是这样的话会很好)。
单例范围
-- Ranges of exactly 1 event
SELECT lt1.user_id, lt1.event_time AS min_time, lt1.event_time AS max_time
FROM Large_Table AS lt1
WHERE NOT EXISTS -- an earlier event that is close enough
(SELECT *
FROM Large_Table AS lt3
WHERE lt1.user_id = lt3.user_id
AND lt3.event_time > lt1.event_time - 3 UNITS HOUR
AND lt3.event_time < lt1.event_time
)
AND NOT EXISTS -- a later event that is close enough
(SELECT *
FROM Large_Table AS lt4
WHERE lt1.user_id = lt4.user_id
AND lt4.event_time > lt1.event_time
AND lt4.event_time < lt1.event_time + 3 UNITS HOUR
)
ORDER BY User_ID, Min_Time;
道尔顿山脉
-- Ranges of exactly 2 events
SELECT lt1.user_id, lt1.event_time AS min_time, lt2.event_time AS max_time
FROM Large_Table AS lt1
JOIN Large_Table AS lt2
ON lt1.user_id = lt2.user_id
AND lt1.event_time < lt2.event_time
AND lt2.event_time < lt1.event_time + 3 UNITS HOUR
WHERE NOT EXISTS -- an earlier event that is close enough
(SELECT *
FROM Large_Table AS lt3
WHERE lt1.user_id = lt3.user_id
AND lt3.event_time > lt1.event_time - 3 UNITS HOUR
AND lt3.event_time < lt1.event_time
)
AND NOT EXISTS -- a later event that is close enough
(SELECT *
FROM Large_Table AS lt4
WHERE lt1.user_id = lt4.user_id
AND lt4.event_time > lt2.event_time
AND lt4.event_time < lt2.event_time + 3 UNITS HOUR
)
AND NOT EXISTS -- any event in between
(SELECT *
FROM Large_Table AS lt5
WHERE lt1.user_id = lt5.user_id
AND lt5.event_time > lt1.event_time
AND lt5.event_time < lt2.event_time
)
ORDER BY User_ID, Min_Time;
在外部 WHERE 子句中添加了 3 小时标准。
多个事件范围
-- Ranges of 3 or more events
SELECT lt1.user_id, lt1.event_time AS min_time, lt2.event_time AS max_time
FROM Large_Table AS lt1
JOIN Large_Table AS lt2
ON lt1.user_id = lt2.user_id
AND lt1.event_time < lt2.event_time
WHERE NOT EXISTS -- an earlier event that is close enough
(SELECT *
FROM Large_Table AS lt3
WHERE lt1.user_id = lt3.user_id
AND lt3.event_time > lt1.event_time - 3 UNITS HOUR
AND lt3.event_time < lt1.event_time
)
AND NOT EXISTS -- a later event that is close enough
(SELECT *
FROM Large_Table AS lt4
WHERE lt1.user_id = lt4.user_id
AND lt4.event_time > lt2.event_time
AND lt4.event_time < lt2.event_time + 3 UNITS HOUR
)
AND NOT EXISTS -- a gap that's too big in the events between first and last
(SELECT *
FROM Large_Table AS lt5 -- E5 before E6
JOIN Large_Table AS lt6
ON lt5.user_id = lt6.user_id
AND lt5.event_time < lt6.event_time
WHERE lt1.user_id = lt5.user_id
AND lt6.event_time < lt2.event_time
AND lt5.event_time > lt1.event_time
AND (lt6.event_time - lt5.event_time) > 3 UNITS HOUR
AND NOT EXISTS -- an event in between these two
(SELECT *
FROM Large_Table AS lt9
WHERE lt5.user_id = lt9.user_id
AND lt9.event_time > lt5.event_time
AND lt9.event_time < lt6.event_time
)
)
AND EXISTS -- an event close enough after the start
(SELECT *
FROM Large_Table AS lt7
WHERE lt1.user_id = lt7.user_id
AND lt1.event_time < lt7.event_time
AND lt7.event_time < lt1.event_time + 3 UNITS HOUR
AND lt7.event_time < lt2.event_time
)
AND EXISTS -- an event close enough before the end
(SELECT *
FROM Large_Table AS lt8
WHERE lt2.user_id = lt8.user_id
AND lt2.event_time > lt8.event_time
AND lt8.event_time > lt2.event_time - 3 UNITS HOUR
AND lt8.event_time > lt1.event_time
)
ORDER BY User_ID, Min_Time;
在“big gaps”子查询中添加了省略的嵌套 NOT EXISTS 子句。
大表中的所有范围
显然,最后一个表中的完整范围列表是上述三个查询的并集。
查询因为不够有趣而被删除。它只是上面单独查询的 3 路 UNION。
最终查询
最后的查询在与小表中的条目足够接近的可怕的 3 部分 UNION 的结果中找到范围(如果有)。例如,小表中的单个条目可能落在 13:00,大表中可能有一个范围在 11:00 结束,另一个从 15:00 开始。大表中的两个范围是分开的(它们之间的间隔是 4 小时),但小表中的条目足够接近,可以计算。[测试涵盖了这种情况。]
SELECT S.User_id, S.Event_Time, L.Min_Time, L.Max_Time, S.Other_Data
FROM Small_Table AS S
JOIN (
-- Ranges of exactly 1 event
SELECT lt1.user_id, lt1.event_time AS min_time, lt1.event_time AS max_time
FROM Large_Table AS lt1
WHERE NOT EXISTS -- an earlier event that is close enough
(SELECT *
FROM Large_Table AS lt3
WHERE lt1.user_id = lt3.user_id
AND lt3.event_time > lt1.event_time - 3 UNITS HOUR
AND lt3.event_time < lt1.event_time
)
AND NOT EXISTS -- a later event that is close enough
(SELECT *
FROM Large_Table AS lt4
WHERE lt1.user_id = lt4.user_id
AND lt4.event_time > lt1.event_time
AND lt4.event_time < lt1.event_time + 3 UNITS HOUR
)
UNION
-- Ranges of exactly 2 events
SELECT lt1.user_id, lt1.event_time AS min_time, lt2.event_time AS max_time
FROM Large_Table AS lt1
JOIN Large_Table AS lt2
ON lt1.user_id = lt2.user_id
AND lt1.event_time < lt2.event_time
AND lt2.event_time < lt1.event_time + 3 UNITS HOUR
WHERE NOT EXISTS -- an earlier event that is close enough
(SELECT *
FROM Large_Table AS lt3
WHERE lt1.user_id = lt3.user_id
AND lt3.event_time > lt1.event_time - 3 UNITS HOUR
AND lt3.event_time < lt1.event_time
)
AND NOT EXISTS -- a later event that is close enough
(SELECT *
FROM Large_Table AS lt4
WHERE lt1.user_id = lt4.user_id
AND lt4.event_time > lt2.event_time
AND lt4.event_time < lt2.event_time + 3 UNITS HOUR
)
AND NOT EXISTS -- any event in between
(SELECT *
FROM Large_Table AS lt5
WHERE lt1.user_id = lt5.user_id
AND lt5.event_time > lt1.event_time
AND lt5.event_time < lt2.event_time
)
UNION
-- Ranges of 3 or more events
SELECT lt1.user_id, lt1.event_time AS min_time, lt2.event_time AS max_time
FROM Large_Table AS lt1
JOIN Large_Table AS lt2
ON lt1.user_id = lt2.user_id
AND lt1.event_time < lt2.event_time
WHERE NOT EXISTS -- an earlier event that is close enough
(SELECT *
FROM Large_Table AS lt3
WHERE lt1.user_id = lt3.user_id
AND lt3.event_time > lt1.event_time - 3 UNITS HOUR
AND lt3.event_time < lt1.event_time
)
AND NOT EXISTS -- a later event that is close enough
(SELECT *
FROM Large_Table AS lt4
WHERE lt1.user_id = lt4.user_id
AND lt4.event_time > lt2.event_time
AND lt4.event_time < lt2.event_time + 3 UNITS HOUR
)
AND NOT EXISTS -- a gap that's too big in the events between first and last
(SELECT *
FROM Large_Table AS lt5 -- E5 before E6
JOIN Large_Table AS lt6
ON lt5.user_id = lt6.user_id
AND lt5.event_time < lt6.event_time
WHERE lt1.user_id = lt5.user_id
AND lt6.event_time < lt2.event_time
AND lt5.event_time > lt1.event_time
AND (lt6.event_time - lt5.event_time) > 3 UNITS HOUR
AND NOT EXISTS -- an event in between these two
(SELECT *
FROM Large_Table AS lt9
WHERE lt5.user_id = lt9.user_id
AND lt9.event_time > lt5.event_time
AND lt9.event_time < lt6.event_time
)
)
AND EXISTS -- an event close enough after the start
(SELECT *
FROM Large_Table AS lt7
WHERE lt1.user_id = lt7.user_id
AND lt1.event_time < lt7.event_time
AND lt7.event_time < lt1.event_time + 3 UNITS HOUR
AND lt7.event_time < lt2.event_time
)
AND EXISTS -- an event close enough before the end
(SELECT *
FROM Large_Table AS lt8
WHERE lt2.user_id = lt8.user_id
AND lt2.event_time > lt8.event_time
AND lt8.event_time > lt2.event_time - 3 UNITS HOUR
AND lt8.event_time > lt1.event_time
)
) AS L
ON S.User_ID = L.User_ID
WHERE S.Event_Time > L.Min_Time - 3 UNITS HOUR
AND S.Event_Time < L.Max_Time + 3 UNITS HOUR
ORDER BY User_ID, Event_Time, Min_Time;
OK - 公平警告;SQL 实际上并没有靠近 SQL DBMS。
代码现在已经过测试。极小的机会实际上是零。有一个语法错误和几个或多或少的小问题需要解决。
在设计了测试数据后,我分阶段进行了实验。我在验证和修复查询时使用了“Alpha”数据(见下文),并添加了 Beta 数据只是为了确保不同的 User_ID 值之间没有串扰。
我使用了显式<
和>
操作而不是BETWEEN ... AND
排除端点;如果您希望恰好相隔 3 小时的事件算作“足够接近”,那么您需要查看每个不等式,可能将它们更改为BETWEEN ... AND
或可能仅使用>=
或<=
酌情使用。
有一个松散相似但相当简单的问题的答案,(a)我写的和(b)对上面的复杂处理提供了一些有用的想法(特别是,'没有事件早但足够接近'和'没有事件稍后但接近“足够”的标准。“足够接近”的标准肯定会使这个问题复杂化。
测试数据
大桌子
CREATE TABLE Large_Table
(
Event_Time DATETIME YEAR TO MINUTE NOT NULL,
User_ID CHAR(15) NOT NULL,
Other_Data INTEGER NOT NULL,
PRIMARY KEY(User_ID, Event_Time)
);
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 09:15', 'Alpha', 1) { R4 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 11:15', 'Alpha', 2) { R4 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 13:15', 'Alpha', 3) { R4 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 15:15', 'Alpha', 4) { R4 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 12:17', 'Beta', 1) { R4 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 09:15', 'Alpha', 5) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 10:17', 'Beta', 2) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-03 09:15', 'Alpha', 6) { R2 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-03 11:15', 'Alpha', 7) { R2 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-03 10:17', 'Beta', 3) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 09:15', 'Alpha', 8) { R3 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 11:15', 'Alpha', 9) { R3 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 13:15', 'Alpha', 10) { R3 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 10:17', 'Beta', 4) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 09:15', 'Alpha', 11) { R2 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 11:15', 'Alpha', 12) { R2 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 10:17', 'Beta', 5) { R1 };
{ Probe here }
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 15:15', 'Alpha', 13) { R2 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 17:15', 'Alpha', 14) { R2 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 16:17', 'Beta', 6) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 09:15', 'Alpha', 15) { R6 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 11:15', 'Alpha', 16) { R6 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 13:15', 'Alpha', 17) { R6 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 15:15', 'Alpha', 18) { R6 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 17:15', 'Alpha', 19) { R6 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 19:15', 'Alpha', 20) { R6 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 16:17', 'Beta', 7) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 09:15', 'Alpha', 21) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 11:17', 'Beta', 8) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 12:15', 'Alpha', 22) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 13:17', 'Beta', 9) { R1 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 09:15', 'Alpha', 23) { R5 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 11:15', 'Alpha', 24) { R5 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 13:15', 'Alpha', 25) { R5 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 15:15', 'Alpha', 26) { R5 };
INSERT INTO Large_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 17:15', 'Alpha', 27) { R5 };
小桌子
注意:为了测试的目的,小表实际上比大表包含更多的行。小表中 Other_Data 值大于 100 的行不应出现在结果中(也不应该出现)。这里的测试确实戳到了边缘条件。
CREATE TABLE Small_Table
(
Event_Time DATETIME YEAR TO MINUTE NOT NULL,
User_ID CHAR(15) NOT NULL,
Other_Data INTEGER NOT NULL,
PRIMARY KEY(User_ID, Event_Time)
);
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 06:15', 'Alpha', 131) { XX };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 06:20', 'Alpha', 31) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 10:20', 'Alpha', 32) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 13:20', 'Alpha', 33) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 15:20', 'Alpha', 34) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 18:15', 'Alpha', 134) { XX };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 06:15', 'Alpha', 135) { XX };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 06:16', 'Alpha', 35) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 10:20', 'Alpha', 35) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 12:14', 'Alpha', 35) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 12:15', 'Alpha', 135) { XX };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-03 09:20', 'Alpha', 36) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-03 11:20', 'Alpha', 37) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 09:20', 'Alpha', 38) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 11:20', 'Alpha', 39) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 13:20', 'Alpha', 40) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 09:20', 'Alpha', 41) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 11:20', 'Alpha', 42) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 13:20', 'Alpha', 42) { 22 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 15:20', 'Alpha', 43) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 17:20', 'Alpha', 44) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 09:20', 'Alpha', 45) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 11:20', 'Alpha', 46) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 13:20', 'Alpha', 47) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 15:20', 'Alpha', 48) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 17:20', 'Alpha', 49) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 19:20', 'Alpha', 50) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 09:20', 'Alpha', 51) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 10:20', 'Alpha', 51) { 22 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 12:20', 'Alpha', 52) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 09:20', 'Alpha', 53) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 11:20', 'Alpha', 54) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 13:20', 'Alpha', 55) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 15:20', 'Alpha', 56) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-08 17:20', 'Alpha', 57) { YY };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 13:27', 'Beta', 9) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-07 11:27', 'Beta', 8) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-06 16:27', 'Beta', 7) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 16:27', 'Beta', 6) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-05 10:27', 'Beta', 5) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-04 10:27', 'Beta', 4) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-03 10:27', 'Beta', 3) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-02 10:27', 'Beta', 2) { R1 };
INSERT INTO Small_Table(Event_Time, User_ID, Other_Data) VALUES('2012-01-01 12:27', 'Beta', 1) { R4 };
最终查询结果
使用上面的数据,得到的结果是:
Alpha 2012-01-01 06:20 2012-01-01 09:15 2012-01-01 15:15 31
Alpha 2012-01-01 10:20 2012-01-01 09:15 2012-01-01 15:15 32
Alpha 2012-01-01 13:20 2012-01-01 09:15 2012-01-01 15:15 33
Alpha 2012-01-01 15:20 2012-01-01 09:15 2012-01-01 15:15 34
Alpha 2012-01-02 06:16 2012-01-02 09:15 2012-01-02 09:15 35
Alpha 2012-01-02 10:20 2012-01-02 09:15 2012-01-02 09:15 35
Alpha 2012-01-02 12:14 2012-01-02 09:15 2012-01-02 09:15 35
Alpha 2012-01-03 09:20 2012-01-03 09:15 2012-01-03 11:15 36
Alpha 2012-01-03 11:20 2012-01-03 09:15 2012-01-03 11:15 37
Alpha 2012-01-04 09:20 2012-01-04 09:15 2012-01-04 13:15 38
Alpha 2012-01-04 11:20 2012-01-04 09:15 2012-01-04 13:15 39
Alpha 2012-01-04 13:20 2012-01-04 09:15 2012-01-04 13:15 40
Alpha 2012-01-05 09:20 2012-01-05 09:15 2012-01-05 11:15 41
Alpha 2012-01-05 11:20 2012-01-05 09:15 2012-01-05 11:15 42
Alpha 2012-01-05 13:20 2012-01-05 09:15 2012-01-05 11:15 42
Alpha 2012-01-05 13:20 2012-01-05 15:15 2012-01-05 17:15 42
Alpha 2012-01-05 15:20 2012-01-05 15:15 2012-01-05 17:15 43
Alpha 2012-01-05 17:20 2012-01-05 15:15 2012-01-05 17:15 44
Alpha 2012-01-06 09:20 2012-01-06 09:15 2012-01-06 19:15 45
Alpha 2012-01-06 11:20 2012-01-06 09:15 2012-01-06 19:15 46
Alpha 2012-01-06 13:20 2012-01-06 09:15 2012-01-06 19:15 47
Alpha 2012-01-06 15:20 2012-01-06 09:15 2012-01-06 19:15 48
Alpha 2012-01-06 17:20 2012-01-06 09:15 2012-01-06 19:15 49
Alpha 2012-01-06 19:20 2012-01-06 09:15 2012-01-06 19:15 50
Alpha 2012-01-07 09:20 2012-01-07 09:15 2012-01-07 09:15 51
Alpha 2012-01-07 09:20 2012-01-07 12:15 2012-01-07 12:15 51
Alpha 2012-01-07 10:20 2012-01-07 09:15 2012-01-07 09:15 51
Alpha 2012-01-07 10:20 2012-01-07 12:15 2012-01-07 12:15 51
Alpha 2012-01-07 12:20 2012-01-07 12:15 2012-01-07 12:15 52
Alpha 2012-01-08 09:20 2012-01-08 09:15 2012-01-08 17:15 53
Alpha 2012-01-08 11:20 2012-01-08 09:15 2012-01-08 17:15 54
Alpha 2012-01-08 13:20 2012-01-08 09:15 2012-01-08 17:15 55
Alpha 2012-01-08 15:20 2012-01-08 09:15 2012-01-08 17:15 56
Alpha 2012-01-08 17:20 2012-01-08 09:15 2012-01-08 17:15 57
Beta 2012-01-01 12:27 2012-01-01 12:17 2012-01-01 12:17 1
Beta 2012-01-02 10:27 2012-01-02 10:17 2012-01-02 10:17 2
Beta 2012-01-03 10:27 2012-01-03 10:17 2012-01-03 10:17 3
Beta 2012-01-04 10:27 2012-01-04 10:17 2012-01-04 10:17 4
Beta 2012-01-05 10:27 2012-01-05 10:17 2012-01-05 10:17 5
Beta 2012-01-05 16:27 2012-01-05 16:17 2012-01-05 16:17 6
Beta 2012-01-06 16:27 2012-01-06 16:17 2012-01-06 16:17 7
Beta 2012-01-07 11:27 2012-01-07 11:17 2012-01-07 13:17 8
Beta 2012-01-07 13:27 2012-01-07 11:17 2012-01-07 13:17 9
中间结果
效果略有不同的格式。
单例范围
Alpha|2012-01-02 09:15|2012-01-02 09:15
Alpha|2012-01-07 09:15|2012-01-07 09:15
Alpha|2012-01-07 12:15|2012-01-07 12:15
Beta|2012-01-01 12:17|2012-01-01 12:17
Beta|2012-01-02 10:17|2012-01-02 10:17
Beta|2012-01-03 10:17|2012-01-03 10:17
Beta|2012-01-04 10:17|2012-01-04 10:17
Beta|2012-01-05 10:17|2012-01-05 10:17
Beta|2012-01-05 16:17|2012-01-05 16:17
Beta|2012-01-06 16:17|2012-01-06 16:17
道尔顿山脉
Alpha|2012-01-03 09:15|2012-01-03 11:15
Alpha|2012-01-05 09:15|2012-01-05 11:15
Alpha|2012-01-05 15:15|2012-01-05 17:15
Beta|2012-01-07 11:17|2012-01-07 13:17
多个事件范围
Alpha|2012-01-01 09:15|2012-01-01 15:15
Alpha|2012-01-04 09:15|2012-01-04 13:15
Alpha|2012-01-06 09:15|2012-01-06 19:15
Alpha|2012-01-08 09:15|2012-01-08 17:15