--- In firebird-support@yahoogroups.com, "Bogdan Mugerli"
<mugerlibogdan@e...> wrote:

> When I've first encountered this, i solved it immediately and then

tested in

> local database and found out that
> if iuse field from outer select or conditions in subselects - the

results

> aren't predictable anymore.

Bogdan, _parameters_ in both outer select and subselect are'nt
predictable. Not always and I can't recall exactly all cases, but the
same parameter - definitily yes. Unpredictablennes in case of usage
columns of outer select in subselect is possible _only_ in case of
improper aliases usage. This is the reason while strong check of such
an ambiguity was introduced in dialect 3, ambigious queries are
rejected on parser level. Unfortunately (IMO) this check was'nt forced
in dialect 1 for compatibility with old applications and I myself
several times stepped on this rake by careless mistake.

Best regards,
Alexander.