建立一個demo表 department：

create table department (
 code VARCHAR2(10) not null,
 name VARCHAR2(50),
 pcode VARCHAR2(10),
 mgrname VARCHAR2(50)
);
insert into department values('ROOT','頂級部門', null, 'R大大');
insert into department values('A','A部門', 'ROOT', 'A老大');
insert into department values('A01','A01部門', 'A', 'A01老大');
insert into department values('A02','A02部門', 'A', 'A02老大');
insert into department values('B','B部門', 'ROOT', 'B老大');
insert into department values('B01','B01部門', 'B', 'B01老大');
insert into department values('B02','B02部門', 'B', 'B02老大');

1.遞迴查詢某個部門的所有子級部門：　

select t.* from department t start with t.code='ROOT' connect by prior t.code = t.pcode ;

　　查詢結果：

2.遞迴查詢某個部門的所有上級部門：

select t.* from department t start with t.code='B02' connect by t.code = prior t.pcode ;

　　查詢結果：