oracle connect by用法

就不转载原文了,来个更加简单易懂的说法.

有数据表   a:

 no               upno
010102       0101
010101       0101
0101           01
01 

select * from a start with no='010101' connect by  no=prior upno;

查询结果为:

010101

0101

01

将upno和no换个位置:
select * from a start with no='0101' connect by  upno=prior no;

查询结果为:

0101

010101

010102

注:

select * from emp connect by upno=prior no start with no='0101';

//与select * from a start with no='0101' connect by upno=prior no;效果一致

与select * from emp connect by prior upno=no start with no='0101';效果相反

重点在于prior的位置




原文:http://www.cnblogs.com/linjiqin/p/3152690.html:

select * from a start with no='010101' connect by  no=prior upno;