我正在使用facade但在var_dump中没有得到响应

Question

门面

$privacy=ProfilePrivacy::get_by_contact($id);
                    $access=json_decode($privacy['access_level'],'true');
                    var_dump($privacy);

辅助

public function get_by_contact($id)
    {
        $result=$this->_model->get_by_contact($id);
    }

模型

  public function get_by_contact($id)
    {
        $sql=" SELECT privacy_access.user_id,privacy_access.access_level,privacy_access.status,privacy_access.created_at
            FROM privacy_access
            JOIN contacts ON privacy_access.user_id= contacts.id WHERE privacy_access.user_id=?";
        $privacy = DB::select($sql, [$id]);
        return $privacy;

    }

我正在使用var dump来获取$ privacy的响应但是确定空值