--- In firebird-support@yahoogroups.com, Vlad Horsun <hvlad@...>
wrote:

>
> > I want to scan the two sets, fetching an item from each and

deciding

> > how they match up. As each is consumed, I need to fetch another

one

> > of that kind, producing in the end a sum of payments within a

given

> > period.
> >
> > This is basically a merge problem, but I don't see a way to do

it in

> > PSQL because it looks to me like you have to read all of one set
> > before you can do anything with the other one.
> >
> > Does anyone have any suggestions as to how this could be done

using

> > PSQL? Or SQL for that matter, say with an SP or a UDF in the

join

> > condition?
>
> Explicit CURSORS in FB2's PSQL may help you

I think they will. Thanks!

>
> Regards,
> Vlad
>