Strange interaction of union and expressions

Hello all,

We noticed some very odd behavior today with Postgres 7.4.5

Running the following SQL:

create table a (foo varchar);
insert into a (foo) values ('baz');
create table b (foo varchar);
insert into b (foo) values ('woof');
select '"' || foo || '"' as foo
    from (select foo from a) as bar
        union select foo from b;

Produces this output:

  foo
-------
 "baz"
 woof
(2 rows)

I would expect the following instead:

  foo
-------
 "baz"
 "woof"
(2 rows)

Is this a known issue?  Has it been fixed?

Thanks,

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Aaron Bingham
Software Engineer
Cenix BioScience GmbH
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