$db = new PDO("mysql:host=$hostname;dbname=$database;port=$port", $username, $password);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$query = "SELECT * FROM `registrations` WHERE `exported` = '0'";

$stmt = $db->prepare($query);
$stmt->execute;
var_dump($stmt);

** output **

object(PDOStatement)#2 (1) {
  ["queryString"]=>
  string(52) "SELECT * FROM `registrations` WHERE `exported` = '0'"
}