怎么把一张表列值插入到另一张表相同的列值？

假如我有一张表A和一张表B，AB表的数据如下：

A表
cdefine1 cdefine2 cdefine3
2000-001 00001 应收
2000-003 00002 应收
2000-004 00003 应收
2000-007 00005 应收
2000-009 00006 应收



B表
cdefine1 cdefine2 cdefine3
2000-002 00002 应收
2000-005 00001 应收
2000-006 00003 应收
2000-008 00004 应收
2000-010 00006 应收



其中两张表的结构是一样的，两张表中cdefine1列的值是没有重复的，cdefine2的值有可能重复，cdefine3的值是一样的
想通过SQL语句把两张表结合，最终效果如下：

cdefine1 cdefine2 cdefine3
2000-001 00001 应收
2000-002 00002 应收
2000-003 00002 应收
2000-004 00003 应收
2000-005 00001 应收
2000-006 00003 应收
2000-007 00005 应收
2000-008 00004 应收
2000-009 00006 应收
2000-010 00006 应收


但是我只想显示出cdefine1列的数据，请教下应该如何实现？

SQL code

select cdefine1 from A
union
select cdefine1 from B

SQL code

select * from t1
union 
select * from t2

select cdefine1 from A
union
select cdefine1 from B

select * from a
union all
select * from b

SQL code

use Tempdb
go
--> --> 
 
declare @A table([cdefine1] nvarchar(8),[cdefine2] nvarchar(5),[cdefine3] nvarchar(2))
Insert @A
select N'2000-001',N'00001',N'应收' union all
select N'2000-003',N'00002',N'应收' union all
select N'2000-004',N'00003',N'应收' union all
select N'2000-007',N'00005',N'应收' union all
select N'2000-009',N'00006',N'应收'
 

declare @B table([cdefine1] nvarchar(8),[cdefine2] nvarchar(5),[cdefine3] nvarchar(2))
Insert @B
select N'2000-002',N'00002',N'应收' union all
select N'2000-005',N'00001',N'应收' union all
select N'2000-006',N'00003',N'应收' union all
select N'2000-008',N'00004',N'应收' union all
select N'2000-010',N'00006',N'应收'

Select * from @A
UNION 
Select * from @B

SQL code

select cdefine1 from
(
   select * from A
   union 
   select * from B
) t;

SQL code

create view v_t3
as
select * from t1
union 
select * from t2

SQL code

select * from tablaA
UNION
select * from tableB