合并 MySQL/MariaDB 中不同行中同一列的两个单元格的数据

Question

我在寻找这个问题的答案时遇到了麻烦，因为我对术语和 SQL 缺乏了解，尽管我知道它可能存在。

我有一个包含下表的数据库：
desc pkm;

+-----------------+---------------+------+-----+---------+-------+
| Field           | Type          | Null | Key | Default | Extra |
+-----------------+---------------+------+-----+---------+-------+
| pkm_code        | int(11)       | NO   | PRI | NULL    |       |
| pkm_name        | varchar(32)   | NO   | UNI | NULL    |       |
| pkm_category    | varchar(32)   | NO   |     | NULL    |       |
| pkm_description | varchar(1280) | NO   |     | NULL    |       |
| pkm_weight      | float         | NO   |     | NULL    |       |
| evolution_code  | int(11)       | YES  | MUL | NULL    |       |
+-----------------+---------------+------+-----+---------+-------+

desc poketype;

+---------------------+------------+------+-----+---------+-------+
| Field               | Type       | Null | Key | Default | Extra |
+---------------------+------------+------+-----+---------+-------+
| pkm_code            | int(11)    | NO   | PRI | NULL    |       |
| type_code           | int(11)    | NO   | PRI | NULL    |       |
| poketype_is_primary | tinyint(1) | NO   |     | NULL    |       |
+---------------------+------------+------+-----+---------+-------+

描述类型；

+-----------+-------------+------+-----+---------+-------+
| Field     | Type        | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| type_code | int(11)     | NO   | PRI | NULL    |       |
| type_name | varchar(32) | NO   | UNI | NULL    |       |
+-----------+-------------+------+-----+---------+-------+

到目前为止，我有以下 SQL 命令：

SELECT pkm.pkm_code, pkm.pkm_name,type.type_name FROM poketype
    JOIN pkm ON pkm.pkm_code=poketype.pkm_code
    JOIN type ON poketype.type_code=type.type_code
    WHERE pkm.pkm_code<=151
    ORDER BY pkm_code;

在不同的行上显示主要类型和次要类型。
对于双重类型的神奇宝贝，我如何让两种类型显示在同一行？

我目前的成绩：

+-----------+-------------+-----------+
| pkm_code  | pkm_name    | type_name |
+-----------+-------------+-----------+
| 1         | Bulbasaur   | grass     |
| 1         | Bulbasaur   | poison    |

期望的结果：

+-----------+-------------+-------------+
| pkm_code  | pkm_name    | type_name   |
+-----------+-------------+-------------+
| 1         | Bulbasaur   | grass,poison|

（是的，bulbasaur是双重类型，我也很惊讶！）

Answer 1

使用 mysql 的 group_concat() function 将来自不同记录的值合并为一个值：

SELECT pkm.pkm_code, pkm.pkm_name, group_concat(type.type_name) as typename FROM poketype
    JOIN pkm ON pkm.pkm_code=poketype.pkm_code
    JOIN type ON poketype.type_code=type.type_code
    WHERE pkm.pkm_code<=151
    GROUP BY pkm.pkm_code, pkm.pkm_name;

合并 MySQL/MariaDB 中不同行中同一列的两个单元格的数据

Merge data from two cells from the same column in different rows in MySQL/MariaDB

mysql

sql

mariadb