Question

在不同服务器上的两个不同数据库中有两个视图，我需要加入它们以便进行少量查询。

我有哪些选项？

我该怎么办？

在同一个数据库中加入视图正在运行。

SELECT * FROM view1
UNION ALL
SELECT * FROM view2

感谢

Answer 1

您可以在mysql中使用联合功能。

在您的mysql中启用联合

使用root（或具有足够权限的其他帐户）登录mysql CLI。

输入：show engines; 此时您应该看不到FEDERATED引擎，如下所示：

mysql> show engines;
+------------+---------+------------------------------------------------------------+---    -----------+------+------------+
| Engine     | Support | Comment                                                    |  Transactions | XA   | Savepoints |
+------------+---------+------------------------------------------------------------+--- -----------+------+------------+
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                      | NO               | NO   | NO         |
| CSV        | YES     | CSV storage engine                                         | NO            | NO   | NO         |
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance     | NO           | NO   | NO         |
| InnoDB     | YES     | Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables  | NO            | NO   | NO         |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
5 rows in set (0.00 sec)

要启用联盟引擎，请键入以下内容：

install plugin federated soname 'ha_federated.so';

不要小心，如果你得到ERROR 1125（HY000）：功能'联合'已经存在

您现在可以安全地将“联合”行添加到/etc/my.cnf文件中，如下所示：

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
federated

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

重启mysqld（服务mysqld restart等等）

重启后，返回mysql CLI。

输入'show engines;' 您现在应该看到FEDERATED引擎可用，并且SUPPORT为YES。

mysql> show engines;
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| Engine     | Support | Comment                                                    | Transactions | XA   | Savepoints |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| FEDERATED  | YES     | Federated MySQL storage engine                             | NO           | NO   | NO         |
| CSV        | YES     | CSV storage engine                                         | NO           | NO   | NO         |
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance     | NO           | NO   | NO         |
| InnoDB     | YES     | Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables  | NO           | NO   | NO         |
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                      | NO           | NO   | NO         |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
6 rows in set (0.00 sec)

重启mysql

service mysqld status
service mysqld stop
service mysqld start

在db1中创建view1，在db2中创建view2

在db1中，

CREATE table federated_table (
id int not null,
name   VARCHAR(32) NOT NULL DEFAULT ''
) 
ENGINE=FEDERATED

CONNECTION='mysql://user_name:password@remote_server_name:3306/db2/view2';

请注意，federated_table和view2必须具有相同的列名称并键入

执行SELECT * FROM db2.federated_table;
执行select * from db1.view1 union all select * FROM db1.federated_table;

参考：http://eves4code.blogspot.in/2015/12/querying-data-by-joining-two-views-in.html

通过在不同服务器上的两个数据库中连接两个视图来查询数据

1 个答案: