select a.num - b.num add_num from (select * from 表A where time='200602')a, (select * from 表A where time='200601') b where a.area1_id = b.area1_id and a.area2_id = b.area2_id and a.type1_id = b.type1_id and a.type2_id = b.type2_id and a.type_3_id = b.type_3_id
select y.time ,y.area1_id , y.area2_id , y.type1_id , y.type2_id , y.type_3_id , y.num-x.num as "add_num" from a x, a y where (x.time=200601 and y.time=200602 and x.type_3_id=y.type_3_id) ;
from (select * from 表A where time='200602')a, (select * from 表A where time='200601') b
where a.area1_id = b.area1_id and a.area2_id = b.area2_id and a.type1_id = b.type1_id and a.type2_id = b.type2_id and a.type_3_id = b.type_3_id
y.num-x.num as "add_num"
from a x, a y
where (x.time=200601 and y.time=200602 and x.type_3_id=y.type_3_id)
;