$dbhost1 = "localhost";
$dbuser1 = "root";
$dbpass1 = "";
$dbname1 = "db1";

$baglan1 = mysql_connect($dbhost1, $dbuser1, $dbpass1);
$dbsec1  = mysql_select_db($dbname1, $baglan1);

$dbhost2 = "localhost";
$dbuser2 = "root";
$dbpass2 = "";
$dbname2 = "db2";

$baglan1 = mysql_connect($dbhost2, $dbuser2, $dbpass2);
$dbsec2  = mysql_select_db($dbname2, $baglan2);

$ilksorgu = mysql_fetch_assoc(mysql_query("SELECT * FROM tablo1", $baglan1));
$id = $ilksorgu['id'];

$ikincisorgu = mysql_query("SELECT * FROM tablo2 WHERE id = '$id'", $baglan2);