使用单个查询（递归查询）在mysql表中查找所有父级

SELECt T2.id, T2.title,T2.controller,T2.method,T2.urlFROM (    SELECt        @r AS _id,        (SELECT @r := parent_id FROM menu WHERe id = _id) AS parent_id,        @l := @l + 1 AS lvl    FROM        (SELECT @r := 31, @l := 0) vars,        menu m    WHERe @r <> 0) T1JOIN menu T2ON T1._id = T2.idORDER BY T1.lvl DESC;

演示版