Have you verified that it returns the correct records? Just asking due
to Bjoern Reimers question about SELECT FIRST not too long ago
(yesterday or today).

Set

--- In firebird-support@yahoogroups.com, "Gary Benade" wrote:
> >> ended up with this, based on your example
> >>
> >> select b.name, count(*) from customers c
> >> join branches b on b.orderappend = c.branchcode and
> >> b.enabled = 'T'
> >> where c.weighted_value >=
> >> (SELECT FIRST 1 SKIP 80000 Weighted_Value FROM Customers
> >> ORDER BY Weighted_Value DESC)
> >> group by 1
>
> > Ann Harrison wrote,
> > Do you have any idea what the performance of that is likely to be?
>
> PLAN (CUSTOMERS ORDER I_CUSTOMERS_WEIGHTEDVALUE)
> PLAN SORT (JOIN (B NATURAL,C INDEX
> (IDX_CUSTOMERS_BRANCHCODE,I_CUSTOMERS_WEIGHTEDVALUE)))
>
> Prep 0.496 sec
> Process 7.156 sec
>
> 65 non indexed reads on branches
> 160,037 indexed reads on customers
>
> very very very impressive compared to the 5+ hour return times of my
> original attempt :)
>
> Regards
> Gary