Hi,
Sometime ago, I posted a question about what I consider to be a bug in
fb, or at least unspecified behavior that I couldn't find documented
anywhere, and nobody could give me a clear answer. So I feel obliged
to resurrect it.

The question was: What happens in a "for select" loop when, inside the
loop, you change something affecting the results of the select, aka
variables, data in tables, anything that could, on a next evaluation
of the select, change its outcome (i.e. more/less rows and/or
different values in those rows).

My opinion based on some tests + practice is that the semantics of the
"for select" are not well defined in this case, and they depend on
various implementation aspects that make the code unpredictable and
unportable. What do you think?

http://tracker.firebirdsql.org/browse/CORE-2166
http://tech.groups.yahoo.com/group/firebird-support/message/98117