Question

Is it possible to UNION queries from tables or views that don’t have any result in common? What I’m trying to do is combine data from different views into one result. I have

select a,b,null,c from VIEW1, VIEW2 where VIEW1.a = VIEW2.a
UNION
select null,null,z,null from VIEW3

I would like the result to be a,b,z,c. Is this where I would use select from? What does that look like?

select ? from (
select a,b,null,c from VIEW1, VIEW2 where VIEW1.a = VIEW2.a
UNION
select null,null,z,null from VIEW3)

I’m using MS SQL Server and the views do not have primary keys. Thanks so much.

Answer 1

If I understand your question, you’re probably getting results like this:

a1, b1, null, c1
a2, b2, null, c2
a3, b2, null, c3
null, null, z1, null
null, null, z2, null
null, null, z3, nul

l

.. but what you’re trying to get are results like this:

a1, b1, z1, c1
a2, b2, z2, c2
a3, b2, z3, c3

Do I understand the problem correctly?

If this is correct, you’ll need to have a way to join these subqueries together, so that you can tell SQL that the 1’s go together, and the 2’s go together, and so on.