--- In firebird-support@yahoogroups.com, "Arno Brinkman"
<fbsupport@...> wrote:

>
> Ok, please give 1.5.3 a try.
> IIRC there was a bug with LEFT JOINs and IS NULL, but only on

specific conditions.

Both 1.5.3 and 2.0 still have the bug. I entered it to the tracker,
please see can you reproduce it:
http://tracker.firebirdsql.org/browse/CORE-1003


ain