<?php
$user = "user";
$pass = "pass";

$connA =  mysql_connect("localhost", $user, $pass);
$connB =  mysql_connect("localhost", $user, $pass, true); //true f�r wirklich neue verbindung
mysql_select_db('drupal', $connA);
mysql_select_db('joomla', $connB);

$resA = mysql_query("select * from users", $connA );
$resB = mysql_query("select * from error", $connB );

echo "<pre>";
while($rowA = mysql_fetch_assoc($resA)){
  print_r($rowA);
}

echo "</pre>
<h1>die zweite DB</h1>
<pre>";
while($rowB = mysql_fetch_assoc($resB)){
  print_r($rowB);
}