Hello Frank,

What you are encountering is that FB is more strict on your SQL than
IB. When migrating from IB, this is one of the issues you are likely
to strike.

Technically it is an ambiguous select. IB will take a wild stab at the
field it thinks you want, but there is probably no more science to its
guess than this field happens to have the name you requested. In this
particular case, there is no problem because both of the ambiguous
fields would contain the same value, but it may not always be that
way. The dangerous situation that may come up is where IB could
potentially choose the incorrect column, and no-one notices.

Also as I learnt last week, FB is going to get more fussy in the
future by rejecting

select cvpmt.acctno from cvpmt p, account a where p.acctno = a.acctno

it will need to be

select p.acctno from cvpmt p, account a where p.acctno = a.acctno

or using the syntax I prefer

select p.acctno
from cvpmt p
join account a on (p.acctno = a.acctno)

I personally think this may introduce unnneccessary obstacles when
porting to FB, but I can understand the decision to head this
direction (such a statement would violate the SQL standard and so may
introduce difficulties porting from FB to something else).

Hope that helps explain something

Adam