MySQL：使用 group_concat 函数连接多行数据为一个字符串

#MySQL 笔记

示例：

建表：

USE test;
CREATE TABLE `test_table` (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `data` varchar(32) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

插入数据：

insert into test_table (data) values('111');
insert into test_table (data) values('222');

查询示例：

mysql root@127.0.0.1:test> select * from test_table
+----+------+
| id | data |
+----+------+
| 1  | 111  |
| 2  | 222  |
+----+------+

mysql root@127.0.0.1:test> select group_concat(data) as result from test_table;
+---------+
| result  |
+---------+
| 111,222 |
+---------+

mysql root@127.0.0.1:test> select group_concat(data) as result from test_table order by id desc;
+---------+
| result  |
+---------+
| 111,222 |
+---------+

mysql root@127.0.0.1:test> select group_concat(data order by id desc) as result from test_table;
+---------+
| result  |
+---------+
| 222,111 |
+---------+

mysql root@127.0.0.1:test> select group_concat(data separator ';') as result from test_table;
+---------+
| result  |
+---------+
| 111;222 |
+---------+