MySQL query on all databases with the same table and column names - mysql

Question

Assume we have the following 2 databases:
DROP DATABASE IF EXISTS `adb`;
CREATE DATABASE `adb` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci;
USE `adb`;
CREATE TABLE IF NOT EXISTS `Login` (
`ID` bigint(20) NOT NULL,
`Login` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`ID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
INSERT INTO `Login` (`ID`, `Login`) VALUES
(1, '2012-11-09 11:18:29'),
(2, '2012-12-22 21:48:48'),
(3, '2013-01-01 12:39:22');
DROP DATABASE IF EXISTS `bdat`;
CREATE DATABASE `bdat` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci;
USE `bdat`;
CREATE TABLE IF NOT EXISTS `Login` (
`ID` bigint(20) NOT NULL,
`Login` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`ID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
INSERT INTO `Login` (`ID`, `Login`) VALUES
(1, '2011-11-09 15:15:15'),
(2, '2012-12-22 13:08:18'),
(3, '2010-02-11 17:00:02');
We also have 2 queries.
Query1 is:
SELECT table_schema AS "Database", round(sum(data_length+index_length)/1024/1024,4) AS "Size (MB)" FROM information_schema.tables GROUP BY table_schema;
Query2 is:
SELECT Max(Login) AS "Last Login" FROM Login
How to combine the two queries together to get the following result ?
Database Size (MB) Last Login
adb 0.0020 2012-12-22 13:08:18
bdat 0.0020 2013-01-01 12:39:22
information_schema 0.0078 NULL
mysql 0.6133 NULL

Answer 1

If you use a Mysql version greater than 5.0 can use FEDERATED TABLES.
For example, in BDAT create a FEDERATED TABLE to ADB, with this code:
CREATE TABLE federated_Login (
`ID` bigint(20) NOT NULL,
`Login` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`ID`)
)
ENGINE=FEDERATED
DEFAULT CHARSET=latin1
CONNECTION='mysql://root#remote_host:9306/federated/Login';
And then you can use federated_Login as a local table for BDAT, for more information:
http://dev.mysql.com/doc/refman/5.0/es/federated-use.html