ORACLE 数据库的级联查询

ORACLE 数据库中可以实现级联查询

select b.comcode          //要查询的字段

from ldcom b                 //具有子接点ID与父接点ID的表

start with b.comcode = '86'                //字段名为子接点ID(给定一个startid)

connect by prior b.comcode=b.upcomcode                //联接条件为子接点等于父接点

----------------------------------------------------------------------下级查询------------------------------------------------------------------------

查询86的下级

select b.comcode
  from ldcom b
 start with b.comcode = '86'

connect by prior b.comcode = b.upcomcode

----------------------------------------------------------------------上级查询--------------------------------------------------------------------------

查询862100的上级

select b.comcode
  from ldcom b
 start with b.comcode = '862100'
connect by prior b.upcomcode = b.comcode