横向子孙树

       $result = $this->m_common->get_all('item_category', ['isrm'=>'0', 'display'=>'1'], '*', 'ordering desc');
       //以id为key值
            $item_categories = [];
            foreach ($result as $key => $value) {
                $item_categories[$value['id']] = $value;
            }
　　　　$this->_get_item_nesting_categories($item_category);
            
   /**
     * 获取部位分类信息 - 数组嵌套方式
     * @return array
     */
    protected function _get_item_nesting_categories($data = []) {
        $new_data = [];
        if ( !empty($data) ) {
            foreach($data as $k=> $v){
                if(isset($data[$v['fid']])){
                    $data[$v['fid']]['child'][$k] = &$data[$k];
                 //   sui($data); exit; 
                }else{
                    $new_data[$k] = &$data[$k];
                }
            }
        }

        return $new_data;
    }