mysql 递归父节点

SELECT t1._id,t1.lvl,t2.title
FROM ( 
    SELECT 
        @r AS _id, 
        (SELECT @r := parent_id FROM request_lists WHERE id = _id) AS parent_id, 
        @l := @l + 1 AS lvl 
    FROM 
        (SELECT @r := 14, @l := 0) vars, 
        request_lists h 
) t1
JOIN request_lists t2 ON t1._id = t2.id
WHERE t1._id>0
ORDER BY t1.lvl DESC