update
  a
set
  aid=b.bid
from
  a join b
on
  a.aid=b.bid

------解决方案--------------------

SQL code

--仅以aid为例

insert into a(aid)
select bid
from b
where not exists (select 1 from a where a.aid = b.bid)

--其他两个字段楼主看情况加，或者和相应表做关联添加吧！