一、用于测试数据及其结构和生成该测试数据的sql语句如下：
1、测试数据
nodeId parentId
---------- ----------
A01 A
A02 A
A03 A
A0101 A01
A0102 A01
A0201 A02
A0202 A02
B01 B
B02 B
B0201 B02
B0202 B02
B020101 B0201
B020102 B0201
2、建表及生成数据的sql语句
create table tree
(
nodeId varchar2(10) not null,
parentId varchar2(10) not null
);
insert into tree
select 'A01', 'A' from dual union all
select 'A02', 'A' from dual union all
select 'A03', 'A' from dual union all
select 'A0101', 'A01' from dual union all
select 'A0102', 'A01' from dual union all
select 'A0201', 'A02' from dual union all
select 'A0202', 'A02' from dual union all
select 'B01', 'B' from dual union all
select 'B02', 'B' from dual union all
select 'B0201', 'B02' from dual union all
select 'B0202', 'B02' from dual union all
select 'B020101', 'B0201' from dual union all
select 'B020102', 'B0201' from dual;
二、递归
1、递归sql
select parentId, nodeId
from tree
start with parentId = 'B02'
connect by parentId = prior nodeId
order by parentId, nodeId;
2、执行结果
parentId nodeId
B02 B0201
B02 B0202
B0201 B020101
B0201 B020102
指定parentId时要注意，oracle是区分大小写的。