Joining unrelated data
Here's an option that uses ROW_NUMBER to create a join based on the order of the ID column from each table.  Naturally, this assumes an equal number of rows in each table.

--demo setup
Declare @T1 table (id int)
Declare @T2 table (id int)

insert into @T1(id) values(1),(2)
insert into @T2(id) values(4),(5)

--solution
select a.id, b.id from 
(
select id, ROW_NUMBER() over(order by id) as rn from @T1
) a
join 
(
select id, ROW_NUMBER() over(order by id) as rn from @T2
) b
on b.rn = a.rn




id  id
1   4
2   5