consult on two db

How I can make a consult between two databases using the same connect.php file?

Regards

When you connect to the database do something like:

$db1 = mysql_connect();
$db2 = mysql_connect();


then in the mysql_query function:
resource mysql_query ( string query [, resource link_identifier] )
you can state which database to use ($db1 or $db2) using the resource link_identifier.