ThinkPHP 是否包含字符

->where(function ($query) {
                $param =  $this->request->param();
                $train_body_id = isset($param['train_body_id'])?$param['train_body_id']:0;
                $query->where('find_in_set(' . $train_body_id . ',train_body_ids ) >0');
            })

find_in_set(keys,column)

返回字符出现的位置，从1开始