mysql 查询数据库 从子到父的sql，以及从父到子所有孩子的接口

select DISTINCT b.* from (SELECT  T2.*
FROM (
    SELECT
        @r AS _id,
        (SELECT @r := parentId FROM t_sys_dept WHERE id = _id) AS parentId,
        @l := @l + 1 AS orderId
    FROM
        (SELECT @r := 'eb1a7acc502b11e88b4222faa7560813', @l := 0) vars,
        t_sys_dept h
    WHERE @r <> 1) sdParent
JOIN t_sys_dept T2
ON sdParent._id = T2.id

ORDER BY sdParent.orderId DESC) b

eb1a7acc502b11e88b4222faa7560813为子节点的id