Oracle兼容层次查询 查询高级特性分析

http://www.365master.com/manage/database/oracle/20080904/36771.shtml

http://blog.csdn.net/xiaoduan9678/archive/2007/07/05/1680261.aspx

http://database.51cto.com/art/200512/12944.htm


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