$sql2 = "SELECT customerid from customer where customer_email = :email";

  $stmt2 = $db->prepare($sql2);
    $stmt2->bindValue(':email', $email, PDO::PARAM_STR);

  $stmt2 -> execute();
  $customerid = $stmt2->fetch();

  echo $customerid['customerid'];
  $id = filter_input(INPUT_GET, 'id');
  echo $id;

  $sql3 = 'INSERT INTO `orders` (`orderid`, `deviceid`, `customerid`) VALUES (NULL,"' . $id . '", "' . $customerid['customerid'] . '")';
  $stmt3= $db->prepare($sql3);


  $stmt3->execute();