codeigniter restful api返回空陣列

我想通過id獲取項目，但它的返回null數組。代碼工作正常，當我獲取所有項目。codeigniter restful api返回空陣列

這裏是控制器：

class Search extends REST_Controller 
{ 

function __construct() 
{ 
    // Construct the parent class 
    parent::__construct(); 
    $this->load->model('Courses_model'); 
    $this->load->model('Courses_category_model'); 
    $this->load->model('Courses_lessons_model'); 
    $this->load->model('Courses_photos_model'); 
    $this->load->model('Providers_model'); 
} 

function index_get() 
{ 
    $category_id = $this->get('category_id'); 

     $result = $this->Courses_model->get_courses_category($category_id); 
      $this->response([ 
      'status' => TRUE, 
      'data' => $result 
     ], REST_Controller::HTTP_OK); 

} 
}

和模型文件是在這裏，模型文件是在這裏：

class Courses_model extends CI_Model 
{ 
public function __construct() 
{ 
    // Call the CI_Model constructor 
    parent::__construct(); 
} 

public function get_courses_category($category_id) 
{ 
    $this->db->where('category_id', $category_id); 
    $query = $this->db->get('courses'); 
    return $query->result(); 
}

來源

2017-08-16 vinn

任何幫助，將不勝感激 – vinn