省市区

select tt.shengid,tt.shengname,tt.shiid,tt.shiname,aa.area_id,aa.area_name from EXPRESSAREA aa

inner join
(select a.area_id shengid,a.area_name shengname,e.area_id shiid,e.area_name shiname,e.parent_area_id from EXPRESSAREA e inner join (select t.area_id,t.area_name from EXPRESSAREA t where t.area_type=1) a on a.area_id=e.parent_area_id and e.area_type=2) tt on tt.shiid=aa.parent_area_id and aa.area_type=3

 

 

思路 先查源表 a  省 然后连接源表 b  查市条件 a.area_id= b .parent_area_id 最后在源表 aa连接(ab)c  条件 c.shiid=aa.parent_area_id