MySQL:选择除列之外只有唯一值的行 [英] MySQL: Select rows that have only unique values except for a column

问题描述

这是我的情况:我有一个重复值有效的表(ID 字段除外)，我只想检索唯一值.

Here is my situation: I have a table which duplicated values are valid (except by the ID field), and I'd like to retrieve only unique values.

例如，如果我有寄存器:

For instance, if I have the registers:

+----+--------------+-------------+------+------+-------+-----+
| ID | SATELLITE_ID | ATT_TYPE_ID | TIME | ROLL | PITCH | YAW |
+----+--------------+-------------+------+------+-------+-----+
|  1 |            1 |           1 | 2012 |  1.0 |   2.0 | 1.3 |
+----+--------------+-------------+------+------+-------+-----+
|  2 |            1 |           1 | 2012 |  1.0 |   2.0 | 1.3 |
+----+--------------+-------------+------+------+-------+-----+
|  3 |            1 |           1 | 2011 |  1.0 |   2.0 | 1.3 |
+----+--------------+-------------+------+------+-------+-----+

我只想检索 2 和 3(ID 1 和 2相等"，而 3 的时间不同).

I'd like to retrieve just 2 and 3 (ID 1 and 2 are "equal", and 3 has different TIME).

这是表结构

mysql> describe attitude;
+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| ID           | int(11)      | NO   | PRI | NULL    | auto_increment |
| SATELLITE_ID | int(11)      | NO   |     | NULL    |                |
| ATT_TYPE_ID  | int(11)      | NO   |     | NULL    |                |
| TIME         | varchar(4)   | NO   |     | NULL    |                |
| ROLL         | double       | NO   |     | NULL    |                |
| PITCH        | double       | NO   |     | NULL    |                |
| YAW          | double       | NO   |     | NULL    |                |
+--------------+--------------+------+-----+---------+----------------+

谢谢.

推荐答案

您可以将 max() 聚合应用于 ID 列，然后 GROUP BY 剩下的:

You can apply the max() aggregate to the ID column and then GROUP BY the rest:

select max(id) id, SATELLITE_ID, ATT_TYPE_ID, TIME, Roll, Pitch, yaw
from attitude
group by SATELLITE_ID, ATT_TYPE_ID, TIME, Roll, Pitch, yaw
order by id

参见SQL Fiddle with Demo

结果:

| ID | SATELLITE_ID | ATT_TYPE_ID | TIME | ROLL | PITCH | YAW |
---------------------------------------------------------------
|  2 |            1 |           1 | 2012 |    1 |     2 |   1 |
|  3 |            1 |           1 | 2011 |    1 |     2 |   1 |

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