如何以逗号分隔获取重复的列值

Question

我有一张这样的表

+----+------------+------------+---------+-----+------+------+
| id | is_deleted | sort_order | version | cid | pid  | qid  |
+----+------------+------------+---------+-----+------+------+
|  1 |            |          1 |       0 |   1 |    1 |    1 |
|  2 |            |          2 |       0 |   1 |    1 |    2 |
|  3 |            |          3 |       0 |   1 |    1 |    3 |
|  4 |            |          1 |       0 |   1 |    2 |    7 |
|  5 |            |          2 |       0 |   1 |    2 |    1 |
|  6 | ☺          |          1 |       1 |   1 |    6 |   14 |
|  7 | ☺          |          1 |       1 |   1 |    5 |   13 |
|  8 |            |          1 |       0 |   1 |    4 |   12 |
|  9 |            |          3 |       0 |   1 |    2 |    2 |
| 10 |            |          4 |       0 |   1 |    1 |    4 |
| 11 |            |          5 |       0 |   1 |    1 |    5 |
+----+------------+------------+---------+-----+------+------+

你可以看到pid重复了。 是否有可能得到以下格式

pid      qid
1     1,2,3,4,5
2     7,1,2
6     14
5     13
4     12

我试过这样，但我得到的输出是

SELECT pid,GROUP_CONCAT(qid) FROM client_parent_question

------+--------------------------+
 pid  | GROUP_CONCAT(qid)        |
------+--------------------------+
    1 | 1,2,3,7,1,14,13,12,2,4,5 |
------+--------------------------+

Answer 1

使用GROUP BY

SELECT pid, GROUP_CONCAT(qid)
FROM client_parent_question
GROUP BY pid

Answer 2

你缺少分组

SELECT pid,GROUP_CONCAT(qid) FROM client_parent_question group by pid

Answer 3

SELECT pid,GROUP_CONCAT(qid) FROM client_parent_question
Group by PID

会做到这一点。输出如下：

pid   |   qid
1     |   1,2,3,4,5
2     |   7,1,2
6     |   14
5     |   13
4     |   12