oracle递归查询示例

CREATE TABLE TBL_TEST
(
   ID     NUMBER,
   NAME   VARCHAR2(100 BYTE),
   PID    NUMBER  DEFAULT 0
);
插入测试数据：
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('1','10','0');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('2','11','1');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('3','20','0');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('4','12','1');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('5','121','2');
从Root往树末梢递归
select * from TBL_TEST
--WHERE connect_by_isleaf=1 取叶节点
start with id=1
connect by prior id = pid
从末梢往树ROOT递归
select * from TBL_TEST
--WHERE connect_by_isleaf=1
start with id=5
connect by prior pid = id