Question

我正在寻找一个SQL查询，它选择x行，其中列最终只有唯一值。

表名为keezdrives_played 列被称为：team_id和opponents_id

[数据库图片。] [1]

这应该是这样的： [实施例] [2]

team_id和opponents_id具有唯一值

Answer 1

您可以使用以下查询执行此操作：

SELECT t.team_id ,o.opponents_id FROM yourTAble t
INNER JOIN (
    SELECT team_id,opponents_id FROM yourTAble
    GROUP BY opponents_id
    HAVING count(*) = 1
) AS o ON o.team_id = t.team_id
GROUP BY t.team_id 
HAVING count(*) = 1;

<强>样品

mysql> select * from yourTable;
+---------+--------------+
| team_id | opponents_id |
+---------+--------------+
|       1 |            5 |
|       1 |            6 |
|       2 |            7 |
|       2 |           80 |
|       3 |            9 |
|       4 |           11 |
|       4 |           22 |
|       8 |            5 |
+---------+--------------+
8 rows in set (0,00 sec)

mysql>     SELECT t.team_id ,o.opponents_id FROM yourTAble t
    ->     INNER JOIN (
    ->         SELECT team_id,opponents_id FROM yourTAble
    ->         GROUP BY opponents_id
    ->         HAVING count(*) = 1
    ->     ) AS o ON o.team_id = t.team_id
    ->     GROUP BY t.team_id
    ->     HAVING count(*) = 1;
+---------+--------------+
| team_id | opponents_id |
+---------+--------------+
|       3 |            9 |
+---------+--------------+
1 row in set (0,00 sec)

mysql>

查看评论

mysql> SELECT count(*) AS cnt , team_id
    -> FROM keezdrives_played
    -> GROUP BY team_id
    -> ;
+-----+---------+
| cnt | team_id |
+-----+---------+
|   4 |    2281 |
|   4 |    2282 |
|   4 |    2283 |
|   4 |    2284 |
|   4 |    2285 |
|   4 |    2286 |
+-----+---------+
6 rows in set (0,00 sec)

mysql>

再试一次

SELECT  team_id,opponents_id
FROM keezdrives_played
GROUP BY CONCAT(team_id, '-', opponents_id)
HAVING count(*) = 1;

上次尝试

SELECT * FROM (
    SELECT t.team_id ,t.opponents_id 
    FROM keezdrives_played t
    GROUP BY t.team_id
    ) r
GROUP BY r.opponents_id;

Answer 2

我希望这就是你想要的

SELECT DISTINCT team_id ,opponents_id  FROM keezdrives_played where drive_id=144;

从2列中选择唯一值

2 个答案: