Mysql 子类查询所有父类

SELECT area_.id, area_.name 
FROM ( 
SELECT 
@r AS _id, 
(SELECT @r := parentid FROM `hk_area` WHERE id = _id) AS parentid, 
@l := @l + 1 AS lvl 
FROM 
(SELECT @r := 2106, @l := 0) vars, 
`hk_area` h 
WHERE @r <> 0) area_1 
JOIN `hk_area` area_
ON area_1._id = area_.id 
ORDER BY area_1.lvl DESC