MySQL 如何将SELECT和SHOW命令结果合并

要将SELECT和SHOW命令结果合并，请使用以下查询语句 –

select @anyVariableName1 as anyAliasName1,@anyVariableName1 as anyAliasName2,......N;

要将SELECT和SHOW命令合并，请先创建和初始化第一个变量。以下是查询语句-

mysql> set @first_name='John';
Query OK, 0 rows affected (0.00 sec)

要将SELECT和SHOW命令合并，请创建和初始化第二个变量。以下是查询语句-

mysql> set @last_name='Smith';
Query OK, 0 rows affected (0.00 sec)

以下是将SELECT和SHOW命令合并的查询语句 –

mysql> select @first_name as EmployeeFirstName,@last_name as EmployeeLastName;

这将产生以下输出 –

+-------------------+------------------+
| EmployeeFirstName | EmployeeLastName |
+-------------------+------------------+
| John              | Smith            |
+-------------------+------------------+
1 row in set (0.00 sec)

要将系统全局变量合并在一起，您可以使用@@代替单个@。以下查询将组合当前MySQL版本和端口号。

以下是查询语句-

mysql> select @@version as CURRENT_MYSQL_VERSION,@@port as
CURRENT_MYSQL_PORT_NUMBER;

这将产生以下输出 –

+-----------------------+---------------------------+
| CURRENT_MYSQL_VERSION | CURRENT_MYSQL_PORT_NUMBER |
+-----------------------+---------------------------+
| 8.0.21                | 3306                      |
+-----------------------+---------------------------+
1 row in set (0.00 sec)

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