[PHP] non prende la query

[sal88]

session_start();


// connect to database
$db = mysqli_connect('localhost', 'user', 'password', 'db');
if($db === false){
  die("error ".mysqli_connect_error());
}

// variable declaration
$username = "";
$email    = "";
$sposo    = "";//sposo
$sposa    = "";//sposa
$errors   = array();

// call the register() function if register_btn is clicked
if (isset($_POST['register_btn'])) {
    register();
}

// REGISTER USER
function register(){
    // call these variables with the global keyword to make them available in function
    global $db, $errors, $username, $email, $sposo, $sposa;//sposo

    // receive all input values from the form. Call the e() function
    // defined below to escape form values
    $username    =  e($_POST['username']);
    $email       =  e($_POST['email']);
    $password_1  =  e($_POST['password_1']);
    $password_2  =  e($_POST['password_2']);
    $sposo       =  e($_POST['sposo']);
    $sposa       =  e($_POST['sposa']);

    // form validation: ensure that the form is correctly filled
    if (empty($username)) {
        array_push($errors, "Username is required");
    }
    if (empty($email)) {
        array_push($errors, "Email is required");
    }
    if (empty($sposo)) {
        array_push($errors, "nome is required");
    }
    if (empty($password_1)) {
        array_push($errors, "Password is required");
    }
    if ($password_1 != $password_2) {
        array_push($errors, "The two passwords do not match");
    }





    // register user if there are no errors in the form
    if (count($errors) == 0) {
        $password = md5($password_1);//encrypt the password before saving in the database

        if (isset($_POST['user_type'])) {
            $user_type = e($_POST['user_type']);
            $query = "INSERT INTO `users`(`username`, `email`, `password`, `user_type`, `sposo`, `sposa`) VALUES
      ('$username', '$email', '$password', '$user_type', '$sposo', '$sposa')";
            mysqli_query($db, $query);
            $_SESSION['success']  = "Account creato!";
            header('location: admin.php');
        }else{
            $query = "INSERT INTO `users`(`username`, `email`, `password`, `user_type`, `sposo`, `sposa`) VALUES
      ('$username', '$email', '$password', '$user_type', '$sposo', '$sposa')";
            mysqli_query($db, $query);

            // get id of the created user
            $logged_in_user_id = mysqli_insert_id($db);

            $_SESSION['user'] = getUserById($logged_in_user_id); // put logged in user in session
            $_SESSION['success']  = "Loggato";
            header('location: index.php');
        }
    }
}