oracle树查询语句

oracle 
select   *   from  tab_organization  start  with   strupcode is null  connect   by   prior   strcode=strupcode  order siblings   by   strcode   asc 

.....start  with  .A... connect   by  prior ...B  ..order  siblings   .C

注意：tab_organization 中的strupcode是父节点的编码,这是一个关联。

A:表示顶级节点的条件，这里是 strupcode is null

B:上下两级节点关联的条件,strcode=strupcode,当前节点的strcode等于下级节点的strupcode.