这个方法只是对Oracle10以上才有效，对sqlserver、mysql没有测试

select connect_by_isleaf isleaf,

            tb.switch_type_id,            sys_connect_by_path(tb.package_id, '|') path,            tb.record_type,            tb.element_offset,            tb.element_length,            tb.element_encode_type,            tb.element_align,            tb.mask,            tb.asn_type            from (select b.switch_type_id,                    b.package_id,                    b.element_offset,                    b.element_length,                    b.element_encode_type,                    nvl(b.element_align, 'L') element_align,                    b.record_type,                    nvl(b.mask, 'LH') mask,                    b.asn_type,                    b.switch_type_id || '|' || b.package_level || '|' || b.package_id level_child,                    b.switch_type_id || '|' || (b.package_level - 1) || '|' || b.parent_package_id level_parent                 from switch_asn_record b                 ) tb             start with tb.level_parent like '%|0|-1'             connect by prior tb.level_child = tb.level_parent;1、connect_by_isleaf是否是子节点；2、sys_connect_by_path(tb.package_id, '|')   ==>  |xxx|xxx|xxx3、start with tb.level_parent like '%|0|-1'  ==> 树的遍历以从什么开始4、connect by prior tb.level_child = tb.level_parent;  ==>此层遍历之后，再将child作为parent，继续往下遍历

 

 

 

select t.*, t.rowid from tbgm_goods_category t

--递归查出指定ID的所有上级节点

SELECT LPAD('',2*(LEVEL - 1), '') || gc.category_id AS category_id,gc.trade_id,gc.parent_category_id

　　FROM tbgm_goods_category gc

　　CONNECT BY PRIOR parent_category_id = category_id -- 找出所有DEPT_ID等于当前记录PARENT_ID的记录

　　START WITH category_id = 216              -- 从部门4开始递归查询。

--递归查出指定ID的所有子级节点SELECT LPAD('',2*(LEVEL - 1), '')||gc.category_id AS category_id,gc.trade_id,gc.parent_category_id,gc.category_depth

　　FROM tbgm_goods_category gc

         where category_depth <= (SELECT category_depth FROM tbgm_goods_category where category_id = 214)+1　　CONNECT BY parent_category_id = PRIOR category_id -- 找出所有PARENT_ID等于当前记录DEPT_ID的记录。

　　START WITH category_id = 214          -- 从部门2开始递归查询。

      

 

oracle 9I中查找一个节点的所有制叶子节点

select   max(t.parent_category_id)keep(dense_rank last order by level)p,  max(t.category_id)keep(dense_rank last order by level)c,  max(t.category_name)keep(dense_rank last order by level)nfrom tbgm_goods_category tstart with t.parent_category_id=259connect by prior t.category_id=t.parent_category_id--and prior child_type=/'special/'group by rownum-level