两列不同

Question

如何从两列中选择唯一结果：

+---------+--------------+
| team_id | opponents_id |
+---------+--------------+
|       1 |            2 |
|       1 |            3 |
|       1 |            4 |
|       1 |            5 |
|       1 |            6 |
|       2 |            1 |
|       2 |            3 |
|       2 |            4 |
|       2 |            5 |
|       2 |            6 |
|       3 |            1 |
|       3 |            2 |
|       3 |            4 |
|       3 |            5 |
|       3 |            6 |
|       4 |            1 |
|       4 |            2 |
|       4 |            3 |
|       4 |            5 |
|       4 |            6 |
|       5 |            1 |
|       5 |            2 |
|       5 |            3 |
|       5 |            4 |
|       5 |            6 |
|       6 |            1 |
|       6 |            2 |
|       6 |            3 |
|       6 |            4 |
|       6 |            5 |
+---------+--------------+

Answer 1

只需使用不同的

 select distinct team_id,opponents_id
   from your_table

Answer 2

如果要根据两列抑制重复，则应使用复合索引column1，column2

对值进行分组

SELECT column1, column2
FROM MA_TABLE
GROUP BY column1, column2

它应该返回一个唯一结果集列表