Oracle 迭代查询 CONNECT BY PRIOR ……START WITH ……

 connect by prior start with 经常会被用到一个表中存在递归关系的时候。比如我们经常会将一个比较复杂的目录树存储到一个表中。或者将一些部门存储到一个表中，而这些部门互相有隶属关系。这个时候你就会用到connect by prior start with。

 表结构：

create table TB_ORG

(

  ORGID            VARCHAR2(50) not null,

  ORGNAME          VARCHAR2(100),

  ORGPARENT        VARCHAR2(50),

)

SQL> select orgid,ORGPARENT from tb_org order by ORGid desc;

ORGID                                              ORGPARENT

-----------------                                   --------------------------------------------------

top_org                                            

newsroom                                      top_org

sjgt                                                 newsroom

bgjsyj                                             newsroom

bgjs                                                newsroom

test52                                            bgjsyj

test36                                            bgjsyj

test3                                              bgjs

test2                                              sjgt

test1                                              sjgt

tes4t1                                             bgjs

--子取父

select * from tb_org CONNECT BY PRIOR orgparent=orgid START WITH orgid='newsroom'

-----子取父变形 （）

select * from tb_org CONNECT BY PRIOR orgparent=orgid START WITH orgparent='newsroom'

--父取子（结果中没有父这条记录）

select * from tb_org CONNECT BY PRIOR orgid=orgparent START WITH orgparent='newsroom'

-----父取子变形（多了父这一级）

select * from tb_org connect by prior orgid=orgparent start with orgid ='newsroom'

 

 

 

注意orgid=orgparent 和orgparent=orgid

转自：http://blog.csdn.net/kenny1985/article/details/3980583