Question

Basically I need to run the following query through jdbc. Both databases are MySQL and on the same server.

SELECT * FROM DB1.ACCOUNT a
JOIN DB2.ITEM i ON a.AccountID = i.AccountID

My jdbc connection is set up like this:

Class.forName("com.mysql.jdbc.Driver").newInstance();
DB1 = DriverManager.getConnection("jdbc:mysql://serverloc.com:3300/DB1", "username", "password");
DB2 = DriverManager.getConnection("jdbc:mysql://serverloc.com:3300/DB2", "username", "password");

This is where I run into problems. I can now create a statement against DB1 or DB2, but I can’t find a way to JOIN against both databases. I’ve tried running my query against one of the databases (below) but that returns null.

Statement statement = DB1.createStatement();
ResultSet resultSet = statement.executeQuery(" QUERY HERE ");

I’ve seen that you can use UnityJDBC to run JOIN queries across DB’s, but I’m looking for a free/open source option.

Thanks!

Answer 1

1) Yes, you can “join” between two different databases in mySQL.

2) No, you don’t need two different connections to do it.

For example:

• http://www.webhostingtalk.com/showthread.php?t=476982

  p2.upc_code FROM db1.products p1 LEFT OUTER JOIN db2.products p2 ON p1.prod_id=p2.prod_id";