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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