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

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

score 0 · Answer 1 · answered Oct 10 '13 at 00:19

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

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

1 Answers1