Oracle Start with...Connect By 使用方法
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