Start with...Connect By子句遞歸查詢(xún)一般用于一個(gè)表維護樹(shù)形結構的應用。
創(chuàng )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(shù)末梢遞歸
select * from TBL_TEST
start with id=1
connect by prior id = pid
從末梢往樹(shù)ROOT遞歸
select * from TBL_TEST
start with id=5
connect by prior pid = id
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