<?php
$utente = $_POST['utente'];
$user = mysql_escape_string($utente);

$pwd = $_POST['password'];
$pass = mysql_escape_string($pwd);

$con = mysql_connect("localhost","user","pass");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_db", $con);

$query = "SELECT url FROM web_login WHERE pass = '$pass' and user='$user'";
    $result = mysql_query($query);

    if (!$result) {
        die("Errore nella query $query: " . mysql_error());
    }

    $record = mysql_fetch_array($result);

    if(!$record) {
        echo "Nessun URL esistente!";
    } else {
                echo $record['url'];
               }

mysql_close($con);

?>