sql 的遞歸含下級查詢（同一張表）

含下級：select  a.id from 表 a start with a.id='123'connect by prior a.id=a.parentid

含上級：select  a.id from 表 a start with a.id='123' connect by prior a.parentid=a.id

含下一級：select  a.id from 表 a start with a.parentid='123' connect by prior a.parentid=a.id