Adam wrote:

> Hi Set,
>
>
>> I don't (yet) agree with Adam and don't think there's any point in
>> changing to a NOT EXISTS ('yet' indicating that I don't use Fb 2.0
>> myself, and that he might have knowledge that I have missed).
>>
>
> Check the Firebird 2 release notes printed page number 102.
>
> [quote]
> Performance
>
> The following changes should be noted as possible sources of
> performance loss:
>
> Existence Predicates NOT IN and ALL May Be Slow
>
> Firebird and, before that, InterBase, have produced incorrect results
> for the logical existence predicates ALL and NOT IN for many years.
> That problem has bee corrected in Firebird 2.0, but the change means
> that indexes on the inner tables cannot be used and performance may be
> slow compared to the same query's performance in V.1.5. "Inner tables"
> are the tables used in the subquery argument inside an ALL or NOT
> IN expression.
>
> Note
>
> NOT EXISTS is approximately equivalent to NOT IN and will allow
> Firebird to use indexes.
>
> [/quote] (sic)
>
>
> Adam
>

I think it's related to sub-queries not a constant list

see you !

--
Alexandre Benson Smith
Development
THOR Software e Comercial Ltda
Santo Andre - Sao Paulo - Brazil
www.thorsoftware.com.br