Oracle的递归查询
收集的几条在oracle中通过connect by prior来实现递归查询
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