Try this:
/*
t1 (1,2,3)
t2(3,4,5)
t3(1,7,8)
t4(3,4,9)
*/
create table dbo.t1 (
id int
)
create table dbo.t2 (
id int
)
create table dbo.t3 (
id int
)
create table dbo.t4 (
id int
)
go
insert into dbo.t1 values (1)
insert into dbo.t1 values (2)
insert into dbo.t1 values (3)
insert into dbo.t1 values (3)
insert into dbo.t1 values (4)
insert into dbo.t1 values (5)
insert into dbo.t1 values (1)
insert into dbo.t1 values (7)
insert into dbo.t1 values (8)
insert into dbo.t1 values (3)
insert into dbo.t1 values (4)
insert into dbo.t1 values (9)
go
select
t1.id
from
dbo.t1
union
select
t2.id
from
dbo.t2
union
select
t3.id
from
dbo.t3
union
select
t4.id
from
dbo.t4
order by
t1.id
go
drop table dbo.t1
drop table dbo.t2
drop table dbo.t3
drop table dbo.t4
go