Update from mysql_* to PDO

gistfile1.php

/**#@+
 * OLD EVIL METHOD
 */
mysql_connect('localhost', $username, $password)
mysql_select_db('App');
$userid = mysql_real_escape_string($_GET['userid']);
$query = <<<SQL 
   SELECT
      username 
   FROM
      Users
   WHERE
      userid = '$userid'
SQL;
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);
      
echo "Hello $row[username]";
/**#@-*/

/**#@+
 * NEW GLORIOUS METHOD
 */
$db = new PDO('mysql:host=localhost;dbname=App', $username, $password)
$userid = $_GET['userid'];
$query = <<<SQL
   SELECT
      username
   FROM
      Users
   WHERE 
      userid = ?
SQL;  
$result = $db->prepare($query);
//execute does not return results; you must do processing on the object.
$result->execute($userid);
$row = $result->fetch();
echo "Hello $row[username].  Your data is safe with PDO!";
/**#@-*/