查询mysql 某个表下一个自增id mysql查询所有下级

SELECT id
  FROM (
      SELECT *
      FROM ty_hotel_product
      WHERE parent_product_id > 0      ORDER BY parent_product_id DESC
  ) realname_sorted, (
          SELECT @pv := 2
      ) initialisation
  WHERE FIND_IN_SET(parent_product_id, @pv) > 0
      AND (@pv := concat(@pv, ',', id))




			select id from (
              select t1.id,
              if(find_in_set(parent_product_id, @pids) > 0, @pids := concat(@pids, ',', id), 0) as ischild
              from (
                   select id,parent_product_id from ty_hotel_product t where t.status = 1 order by parent_product_id, id
                  ) t1,
                  (select @pids := 1) t2
             ) t3 where ischild != 0