WITH RECURSIVE T(n, areaname,areaid,parentid ) AS (

-- 语句块 初始化语句, 只执行一次，初始化添加一个 n = 1
select 1 n, name areaname,areaid,parentid 
from jh_area where parentid = '410000'


UNION ALL

-- 递归语句, 执行n次，控制n，则控制递归的层次
select  (n +1) as n, k.name areaname,k.areaid, k.parentid
from jh_area k, T
where T.areaid = k.parentid 
and n < 4


) select * from T ;