MySQL获取查询中当前行的前后行

我在MySQL中有五个表，我正在从中生成一些报告。为了便于显示，我将稍微抽象表名。假设我使用的表如下所述：

History  (id, serial, date, time) : Stores historic data, this is the main
                                    column we query.
Serial   (id, serial)             : Stores serial numbers used in the next
                                    3 tables.
Employee (id, serial_id, name)
Event    (id, serial_id, name)
Location (id, serial_id, name)

编辑：重写整个问题，希望它更清晰、更容易理解

我需要查询事件，同样，如果在历史记录中直接在序列与事件匹配的行之前找到员工序列，则该员工将与该事件关联，同样，如果在序列与事件匹配的行之后直接在历史记录中找到位置，该位置将与该事件关联

样本数据：

History:
+------+------------+------------+----------+
| id   | serial     | date       | time     |
+------+------------+------------+----------+
| 1    | 00001234   | 2012-09-25 | 09:00:00 |
+------+------------+------------+----------+
| 2    | 00001235   | 2012-09-25 | 09:01:00 |
+------+------------+------------+----------+
| 3    | 00001236   | 2012-09-25 | 09:02:00 |
+------+------------+------------+----------+
| 4    | 00001235   | 2012-09-25 | 09:05:00 |
+------+------------+------------+----------+
| 5    | 00001236   | 2012-09-25 | 09:07:00 |
+------+------------+------------+----------+
| 6    | 00001235   | 2012-09-25 | 09:10:00 |
+------+------------+------------+----------+
| 7    | 00001235   | 2012-09-25 | 09:11:00 |
+------+------------+------------+----------+
| 8    | 00001235   | 2012-09-25 | 09:12:00 |
+------+------------+------------+----------+
| 9    | 00001236   | 2012-09-25 | 09:15:00 |
+------+------------+------------+----------+
| 10   | 00001234   | 2012-09-25 | 09:20:00 |
+------+------------+------------+----------+
| 11   | 00001236   | 2012-09-25 | 09:25:00 |
+------+------------+------------+----------+

Serial:
+----------+------------+
| id       | serial     |
+----------+------------+
| 1        | 00001234   |
+----------+------------+
| 2        | 00001235   |
+----------+------------+
| 3        | 00001236   |
+----------+------------+

Employee:
+----------+------------+-------------+
| id       | serial_id  | name        |
+----------+------------+-------------+
| 1        | 1          | John Smith  |
+----------+------------+-------------+

Event:
+----------+------------+-------------+
| id       | serial_id  | name        |
+----------+------------+-------------+
| 1        | 2          | Event 1     |
+----------+------------+-------------+

Location:
+----------+------------+-------------+
| id       | serial_id  | name        |
+----------+------------+-------------+
| 1        | 3          | Location 1  |
+----------+------------+-------------+

如果我使用以下查询执行正常的左连接查询（只是为了清楚显示结果的差异），结果将是：

SELECT
    history.id,
    history.serial,
    history.date,
    history.time,
    employee.name as 'employee',
    event.name as 'event',
    location.name as 'location'
FROM history
LEFT JOIN serial ON history.serial = serial.serial
LEFT JOIN employee ON serial.id = employee.serial_id
LEFT JOIN event ON serial.id = event.serial_id
LEFT JOIN location ON location.id = location.serial_id
ORDER BY date, time

正常左连接的结果如下（仅为清楚起见，我不需要此结果集）：

查询应基于事件，事件不应为NULL。它应该查看前一行并将其标记为employee（如果不匹配，则为null）；它应该查看后一行并将其标记为location（如果不匹配，则为null）。使用上述数据得出的结果示例：

Result should be:
+----------+------------+------------+------------+----------+------------+
| e_serial | date       | time       | employee   | event    | location   |
+----------+------------+------------+------------+----------+------------+
| 00001235 | 2012-09-25 | 09:01:00   | John Smith | Event 1  | Location 1 |
+----------+------------+------------+------------+----------+------------+
| 00001235 | 2012-09-25 | 09:05:00   | NULL       | Event 1  | Location 1 |
+----------+------------+------------+------------+----------+------------+
| 00001235 | 2012-09-25 | 09:10:00   | NULL       | Event 1  | NULL       |
+----------+------------+------------+------------+----------+------------+
| 00001235 | 2012-09-25 | 09:11:00   | NULL       | Event 1  | NULL       |
+----------+------------+------------+------------+----------+------------+
| 00001235 | 2012-09-25 | 09:12:00   | NULL       | Event 1  | Location 1 |
+----------+------------+------------+------------+----------+------------+

我不确定这在一些子选择集或其他方面是否可行，我认为这远远超过了我使用SQL的能力。目前，我使用应用程序逻辑处理这个问题，但我认为只使用SQL可能会更干净、更快

任何帮助都会很棒

SELECT serial_id AS `serial`,
(SELECT `date` FROM History WHERE serial_id= event2.serial_id ) AS `date`,
(SELECT `time` FROM History WHERE serial_id= event2.serial_id ) AS `time`,
(SELECT `name` FROM event1 WHERE serial_id= event2.serial_id ) AS `event1`,`name` AS event2,
(SELECT `name` FROM event3 WHERE serial_id= event2.serial_id ) AS `event1`
FROM event2

您的历史记录表应该是

历史记录（id、序列号、日期、时间）

，必须包含

序列号

，而不是

序列名

对于您的场景，希望它能正常工作

SELECT serial_id AS `serial`,
(SELECT `date` FROM History WHERE `serial` = (SELECT `serial` FROM `serial` WHERE id = event2.serial_id LIMIT 0,1)) AS `date`,
(SELECT `time` FROM History WHERE `serial`= (SELECT `serial` FROM `serial` WHERE id = event2.serial_id LIMIT 0,1)) AS `time`,
(SELECT `name` FROM event1 WHERE serial_id= event2.serial_id ) AS `event1`,
`name` AS event2,
(SELECT `name` FROM event3 WHERE serial_id= event2.serial_id ) AS `event1`
FROM event2

---

如果其他人遇到这个问题，请在此处发布解决方案。感谢dianuj为我指引了正确的方向

SELECT
    serial.serial as 'e_serial',
    @dt:=TIMESTAMP(history.date, history.time) as 'date_time',
    history.date,
    history.time,
    (SELECT
        employee.name
    FROM
        history
        LEFT JOIN serial ON history.serial = serial.serial
        LEFT JOIN employee ON employee.serial_id = serial.id
    WHERE
        TIMESTAMP(history.date, history.time) = (
            SELECT
                max(TIMESTAMP(history.date, history.time))
            FROM
                history
            WHERE TIMESTAMP(history.date, history.time) < @dt
        )
    ) as 'employee',
    event.name as 'event',
    (SELECT
        location.name
    FROM
        history
        LEFT JOIN serial ON history.serial = serial.serial
        LEFT JOIN location ON location.serial_id = serial.id
    WHERE
        TIMESTAMP(history.date, history.time) > @dt
    LIMIT 1
    ) as 'location'
FROM history
LEFT JOIN serial ON history.serial = serial.serial
LEFT JOIN event ON serial.id = event.serial_id
WHERE event.name IS NOT NULL
ORDER BY history.date, history.time

---

如果您发布每个表的记录而不是连接查询的结果，则会更好：问题是希望它更清楚：）感谢您的回答，不幸的是，无法将serial_id列附加到历史记录表。历史记录中的数据直接来自硬件，硬件提供的所有数据都是序列号。您可以检查第二个查询库，它为我提供了一些帮助，但是您的示例中的event1.serial_id与event2.serial_id不同，因此我无法使用它们加入。我需要的是检查事件2之前和之后的行，并检查匹配项。我想我可能会重写这个问题来澄清，也许它太混乱了。如果你理解上面的mu查询，它只会获取event2表中的

serial\u id

的记录，而不是所有的记录，只获取event2中存在的那些记录，正如你的问题所描述的。希望新问题更有意义

SELECT
    serial.serial as 'e_serial',
    @dt:=TIMESTAMP(history.date, history.time) as 'date_time',
    history.date,
    history.time,
    (SELECT
        employee.name
    FROM
        history
        LEFT JOIN serial ON history.serial = serial.serial
        LEFT JOIN employee ON employee.serial_id = serial.id
    WHERE
        TIMESTAMP(history.date, history.time) = (
            SELECT
                max(TIMESTAMP(history.date, history.time))
            FROM
                history
            WHERE TIMESTAMP(history.date, history.time) < @dt
        )
    ) as 'employee',
    event.name as 'event',
    (SELECT
        location.name
    FROM
        history
        LEFT JOIN serial ON history.serial = serial.serial
        LEFT JOIN location ON location.serial_id = serial.id
    WHERE
        TIMESTAMP(history.date, history.time) > @dt
    LIMIT 1
    ) as 'location'
FROM history
LEFT JOIN serial ON history.serial = serial.serial
LEFT JOIN event ON serial.id = event.serial_id
WHERE event.name IS NOT NULL
ORDER BY history.date, history.time

+----------+---------------------+------------+----------+------------+---------+------------+
| e_serial | date_time           | date       | time     | employee   | event   | location   |
+----------+---------------------+------------+----------+------------+---------+------------+
| 00001235 | 2012-09-25 09:01:00 | 2012-09-25 | 09:01:00 | John Smith | Event 1 | Location 1 |
| 00001235 | 2012-09-25 09:05:00 | 2012-09-25 | 09:05:00 | NULL       | Event 1 | Location 1 |
| 00001235 | 2012-09-25 09:10:00 | 2012-09-25 | 09:10:00 | NULL       | Event 1 | NULL       |
| 00001235 | 2012-09-25 09:11:00 | 2012-09-25 | 09:11:00 | NULL       | Event 1 | NULL       |
| 00001235 | 2012-09-25 09:12:00 | 2012-09-25 | 09:12:00 | NULL       | Event 1 | Location 1 |
+----------+---------------------+------------+----------+------------+---------+------------+
5 rows in set (0.01 sec)