在数据库父子关系的模型中，经常会需要将数据表现为树形，带层次结构的表现，就可以采用connect by prior start with来实现了。

代码

 1:

 

 2: *******************************************************************************/

 

 3:

 

 4: --创建测试表，增加测试数据

 

 5:

 

 6:createtable dapeng_test(superid varchar2(20),id varchar2(20));

 

 7:

 

 8: insert into dapeng_test values('0','1');

 

 9: insert into dapeng_test values('0','2');

 

 10:

 

 11: insert into dapeng_test values('1','11');

 

 12: insert into dapeng_test values('1','12');

 

 13:

 

 14: insert into dapeng_test values('2','21');

 

 15: insert into dapeng_test values('2','22');

 

 16:

 

 17: insert into dapeng_test values('11','111');

 

 18: insert into dapeng_test values('11','112');

 

 19:

 

 20: insert into dapeng_test values('12','121');

 

 21: insert into dapeng_test values('12','122');

 

 22:

 

 23: insert into dapeng_test values('21','211');

 

 24: insert into dapeng_test values('21','212');

 

 25:

 

 26: insert into dapeng_test values('22','221');

 

 27: insert into dapeng_test values('22','222');

 

 28:

 

 29:commit;

 

 30:

 

 31: --层次查询示例

 

 32:selectlevel||'层',lpad(' ',level*5)||id id

 

 33:from dapeng_test

 

 34:startwith superid = '0'connectbyprior id=superid;

 

结果