[英]MySQL: Select rows that have only unique values except for a column
這是我的情況:我有一個表,其中重復的值是有效的(ID字段除外),並且我只想檢索唯一的值。
例如,如果我有寄存器:
+----+--------------+-------------+------+------+-------+-----+
| 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 |
+----+--------------+-------------+------+------+-------+-----+
我只想檢索2和3(ID 1和2是“相等”,而3具有不同的TIME)。
這是表格結構
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 | |
+--------------+--------------+------+-----+---------+----------------+
謝謝。
嘗試:
SELECT DISTINCT SATELLITE_ID, ATT_TYPE_ID, TIME, ROLL, PITCH, YAW
FROM ATTITUDE
您可以將max()
集合應用於ID
列,然后將其余部分應用於GROUP BY
:
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
結果:
| ID | SATELLITE_ID | ATT_TYPE_ID | TIME | ROLL | PITCH | YAW |
---------------------------------------------------------------
| 2 | 1 | 1 | 2012 | 1 | 2 | 1 |
| 3 | 1 | 1 | 2011 | 1 | 2 | 1 |
嘗試這個:
select SATELLITE_ID, ATT_TYPE_ID, TIME, ROLL, PITCH, YAW
from ATTITUDE
group by SATELLITE_ID, ATT_TYPE_ID, TIME, ROLL, PITCH, YAW
或者你可以使用distinct
select distinct SATELLITE_ID, ATT_TYPE_ID, TIME, ROLL, PITCH, YAW
from ATTITUDE
select max(ID) from attitude
group by SATELLITE_ID, ATT_TYPE_ID, TIME, ROLL, PITCH, YAW;
這可以根據SATELLITE_ID,ATT_TYPE_ID,TIME,ROLL,PITCH和YAW的不同值任意分組。 如果您忽略了其中一些字段,那僅意味着組的數量可能會減少,彼此之間差異的原因也就更少。
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