MySQL 如何将两列值连接成一个单独的列，结果列值应用连字符分隔

首先让我们创建一个表 –

mysql> create table DemoTable835(
   CountryCode int,
   CountryName varchar(100)
);
Query OK, 0 rows affected (0.63 sec)

使用insert命令将一些记录插入表中 –

mysql> insert into DemoTable835 values(100,'US');
Query OK, 1 row affected (0.36 sec)
mysql> insert into DemoTable835 values(101,'UK');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable835 values(102,'AUS');
Query OK, 1 row affected (0.26 sec)
mysql> insert into DemoTable835 values(103,'ENG');
Query OK, 1 row affected (0.09 sec)

使用select语句显示表中的所有记录 –

mysql> select *from DemoTable835;

这将产生以下输出 –

+-------------+-------------+
| CountryCode | CountryName |
+-------------+-------------+
|         100 | US          |
|         101 | UK          |
|         102 | AUS         |
|         103 | ENG         |
+-------------+-------------+
4 rows in set (0.00 sec)

以下是将两个列值连接为一个单独列的查询 –

mysql> select concat(CountryCode,'-',CountryName) from DemoTable835;

这将产生以下输出 –

+-------------------------------------+
| concat(CountryCode,'-',CountryName) |
+-------------------------------------+
| 100-US                              |
| 101-UK                              |
| 102-AUS                             |
| 103-ENG                             |
+-------------------------------------+
4 rows in set (0.00 sec)

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