Hi, I think this is a very old question, but I never did it with Firebird
before.

I want to do a simpe current acount with in-out-balance columns. The movements
would come from the invoices and payments tables ordered by date. I usually did
it with triggers that insert the movements in a separate table and re-calculate
all the balances (with a stored procedure) for each record every time something
in inserted, modified or deleted. I wonder if there is a way to do it "on the
fly".. I mean when the user want to see some current account, just do " select
(some fields) from invoices union all select (some fields) from payments order
by 1" (being "1" the pos of the date field). Firts of all, I don't know how fast
would be this approach as the DB gets bigger, and second: I dont know how to
resolve the "balance" column on a select, because it depends on the previous
row. May I have some diferent opinions of experienced people? Thanks!! -s