Oracle用Start with...Connect By子句遞歸查詢

Start with...Connect By子句遞歸查詢一般用于一個表維護樹形結構的應用。
創建示例表：
CREATE TABLE TBL_TEST
(
  ID    NUMBER,
  NAME  VARCHAR2(100 BYTE),
  PID   NUMBER                                  DEFAULT 0
);
 
插入測試數據：
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');
 
從Root往樹末梢遞歸
select * from TBL_TEST
 start with id=1
 connect by prior id = pid
 
從末梢往樹ROOT遞歸
select * from TBL_TEST
 start with id=5
 connect by prior pid = id