>> select a.*, (select count(*) from a1 where a1.b_id = b.id) as F1 from tb a where (select count

(*) from a1 where a1.b_id = b.id) = 100; [Alan]

or if you're using FB2, something like:

select z.* from
(select a.*, (select count(*) from a1 where a1.b_id = b.id) as F1 from tb a) z
where z.F1 = 100;

or if you're using FB2.1, you could also try:

with z (select a.*, (select count(*) from a1 where a1.b_id = b.id) as F1 from tb a)
select z.* from z where z.F1 = 100;

As far as I know, there's no performance difference between any of these options? (incl. Alan's?)

- Philip