connect by prior start with 用法

Oracle用Start with...Connect By子句递归查询 

Start with...Connect By子句递归查询一般用于一个表维护树形结构的应用。

创建示例表：

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
 start with id=1
 connect by prior id = pid

 

从末梢往树ROOT递归

select * from TBL_TEST
 start with id=5
 connect by prior pid = id