多表连接的问题

如何连接，请教了。

表A
Aid Astr AB AC AD 
 1 苹果 1 1 1

表B
Bid Bstr
 1 香蕉

表C
Cid Cstr
 1 橘子

表D
Did Dstr
 1 桃子

想用AB,AC,AD分别与Bid,Cid,Did 链接，最后输出结果是

Aid Astr AB AC AD
 1 苹果 香蕉 橘子 桃子

刚开始学，这个问题纠结很久了，求解答

SQL code

select a.aid,a.astr,b.bstr,c.cstr,d.dstr
from a join b on a.ab = b.bid
       join c on a.ac = c.cid
       join d on a.ad = d.did

多表 inner join ..on

SQL code

--用inner join 内联接
if object_id('a') is not null
   drop table a
go
create table a
(
 aid int,
 astr varchar(10),
 ab int,
 ac int,
 ad int
)
go
insert into a select 1,'苹果',1,1,1
go
if object_id('b') is not null
   drop table b
go
create table b
(
 bid int,
 bstr varchar(10)
)
go
insert into b select 1,'香蕉'
go
if object_id('c') is not null
   drop table c
go
create table c
(
 cid int,
 cstr varchar(10)
)
go
insert into c select 1,'橘子'
go
if object_id('d') is not null
   drop table d
go
create table d
(
 did int,
 dstr varchar(10)
)
go
insert into d select 1,'桃子'
go
select aid,astr,bstr,cstr,dstr
  from a inner join b on a.ab=b.bid
         inner join c on a.ac=c.cid
         inner join d on a.ad=d.did
go
/*
aid         astr       bstr       cstr       dstr
----------- ---------- ---------- ---------- ----------
1           苹果         香蕉         橘子         桃子

(1 行受影响)

*/

SQL code

--改一下列名
if object_id('a') is not null
   drop table a
go
create table a
(
 aid int,
 astr varchar(10),
 ab int,
 ac int,
 ad int
)
go
insert into a select 1,'苹果',1,1,1
go
if object_id('b') is not null
   drop table b
go
create table b
(
 bid int,
 bstr varchar(10)
)
go
insert into b select 1,'香蕉'
go
if object_id('c') is not null
   drop table c
go
create table c
(
 cid int,
 cstr varchar(10)
)
go
insert into c select 1,'橘子'
go
if object_id('d') is not null
   drop table d
go
create table d
(
 did int,
 dstr varchar(10)
)
go
insert into d select 1,'桃子'
go
select aid,astr,ab=bstr,ac=cstr,ad=dstr
  from a inner join b on a.ab=b.bid
         inner join c on a.ac=c.cid
         inner join d on a.ad=d.did
go
/*
aid         astr       ab         ac         ad
----------- ---------- ---------- ---------- ----------
1           苹果         香蕉         橘子         桃子

(1 行受影响)
*/