請告訴我如何解決這個問題，我從我的 PHP CodeIgniter API 得到錯誤錯誤嘗試獲取非對象的屬性“join_id”詢問Select * from join_chat where(user_1 = '24' and user_2 = '26') or(user_1 = '26' and user_2 = '24')result of query+---------+--------+--------+| join_id | user_1 | user_2 |+---------+--------+--------+|      20 | 26     | 24     |+---------+--------+--------+1 row in set (0.01 sec)從結果中，您可以看到連接 ID 返回為 20，但我收到錯誤Trying to get property 'join_id' of non-object請參閱下面的控制器方法 public function get_join_user()    {        $this->load->library('form_validation');        $this->form_validation->set_rules('post_user_id', 'post_user_id', 'trim|required');        $this->form_validation->set_rules('login_user_id', 'login_user_id', 'trim|required');        if ($this->form_validation->run() == false) {            $data["responce"] = false;            $data["error"] = 'field is required';        } else {            $this->load->model("common_model");            $q = $this->db->query("Select * from join_chat where                      (user_1 = '".$this->input->post("login_user_id")."' and user_2 = '".$this->input->post("post_user_id")."') or                      (user_1 = '".$this->input->post("post_user_id")."' and user_2 = '".$this->input->post("login_user_id")."')");            //$row = $q->row();            $row = $q->result();            if (count($row) > 0) {                $data["responce"] = true;                //*****error causing line below***                $data["data"] = $row->join_id;            } 導致錯誤的行$data["data"] = $row->join_id;