drop table test;
create table test
(
 col1 integer,
 col2 varchar(10),
 col3 date
);
insert into test values (1,'Value 1',current_date);
insert into test values (2,'Value 2',current_date);
insert into test values (3,'Value 3',current_date);

select col1, col2, col3
from test
union all
select 10, 'Value', current_date
from test

The rows belonging to the second part of the union have null values in every
column.

UNION DISTINCT works as expected:

select col1, col2, col3
from test
union
select 10, 'Value', current_date
from test

Ole Willy Tuv

Ole,

<< The rows belonging to the second part of the union have null values in
every column. >>

It's the same issue as the 'B' sub-select that you reported.   There's an
issue with live queries and expression columns.   Essentially EDB is not
applying the mapping of the expression columns at the correct time.

--
Tim Young
Elevate Software
www.elevatesoft.com