--- In firebird-support@yahoogroups.com, "Martijn Tonies"
<m.tonies@...> wrote:

> If you want to compare for the state as well, you have
> to modify your code OR use the COALESCE function

if (field1 is null or field1 = field2) then ...
this statement always returs false even if field1 = null :(

even this returns always false:
if (not field1 <> field2) then ...

As I think this should be fixed in future fb releases.