MYSQL递归获取子集 或者 父集

-- 起始值为2，获得所有父节点（包括自己）

SELECT *
FROM ( 
SELECT 
@r AS _guid, 
(SELECT @r := superguid FROM `table` WHERE guid = _guid) AS superguid, 
@l := @l + 1 AS lvl 
FROM 
(SELECT @r := '000', @l := 0) vars,
`table` h 
) T1 
JOIN `table` T2 
ON T1._guid = T2.guid 
ORDER BY T1.lvl DESC

select t.* from (
select @guid idlist,
(select @guid:=group_concat(parentid separator ',') from table where find_in_set(guid,@guid)) sub
from table,(select @guid:='000') vars
where @guid is not null) tl,table t
where find_in_set(t.guid,tl.idlist);

-- 获取所有子子节点包括自己

    select t.* from (
    select @guid idlist,
    (select @guid:=group_concat(guid separator ',') from table where find_in_set(parentid,@guid)) sub
    from table,(select @guid:='000') vars
    where @guid is not null) tl,table t
    where find_in_set(t.guid,tl.idlist);