A表数据
AID AName
1 car
2 book
3 penB表数据
BID AID BName
1 1 auto
2 2 bo
3 2 bo2
4 1 bus要得到
AID AName BName
1 car auto
2 book bo
3 pen <null>sql语句怎么写?在access中写法又是如何?求教
AID AName
1 car
2 book
3 penB表数据
BID AID BName
1 1 auto
2 2 bo
3 2 bo2
4 1 bus要得到
AID AName BName
1 car auto
2 book bo
3 pen <null>sql语句怎么写?在access中写法又是如何?求教
insert a select 1,'car'
union all select 2,'book'
union all select 3,'pen'create table b(BID int,AID int,BName varchar(10))
insert b select 1,1,'auto'
union all select 2,2,'bo'
union all select 3,2,'bo2'
union all select 4,1,'bus'
select a.*,c.bname from a left join (select * from b where bid in(select min(bid) from b group by aid)) c
on a.aid=c.aidselect a.*,c.bname from a left join
(select * from b t where exists(select 1 from b where aid=t.aid and bid>t.bid)) c
on a.aid=c.aid
(select * from b t where not exists(select 1 from b where aid=t.aid and bid<t.bid)) c
on a.aid=c.aid