Codeigniter连接多个表和

class User_model extends CI_Model {
    public function get_user_orders($user_id) {
        $this->db->select('*');
        $this->db->from('users');
        $this->db->join('orders', 'users.user_id = orders.user_id');
        $this->db->where('users.user_id', $user_id);
        $query = $this->db->get();
        return $query->result();
    }
}

class User extends CI_Controller {
    public function index($user_id) {
        $this->load->model('user_model');
        $data['user_orders'] = $this->user_model->get_user_orders($user_id);
        $this->load->view('user_orders', $data);
    }
}

foreach ($user_orders as $order) {
    echo $order->order_id;
    echo $order->order_date;
    // 其他字段...
}