--- In firebird-support@yahoogroups.com, Mark Rotteveel <mark@...> wrote:

>
> On 5-11-2011 12:00, venussoftop wrote:
> >>> I know a qty. for a particular item purchased. This item though has been purchased over a long period only the last few purchase bills are now of concern (FIFO method). I have the following tables
> >>>
> >>> tPurchaseBill
> >>> iID PK
> >>> iNo Bill No.
> >>> etc.
> >>>
> >>> sPurchaseBillItems
> >>> iID PK
> >>> iPID FK to tPurchaseBill table
> >>> iItemID FK to mItems table
> >>> bQty qty. in this purchase
> >>> etc.
> >>>
> >>> so if I am to provide an iItemID and a bStock qty. can I bring out only those last few tPurchaseBill records. Is there any way I can do this in pure SQL?
> >>
> >> Sort by the purchase date descending and use the ROWS clause to limit
> >> the amount of rows returned:
> >> http://www.firebirdsql.org/file/documentation/reference_manuals/reference_material/html/langrefupd25-select.html#langrefupd25-select-rows
> >>
> >
> > Thanks Mark for your response. Yes, I can limit the number of rows to something that is practical and not the whole set. But I do not think I will be able to convert the bStock qty. into number of rows as the qty. would be different in each purchase bill. Any suggestions on this front.
>
> I think you will need to use EXECUTE BLOCK or a selectable PROCEDURE to
> do that.
>
> --
> Mark Rotteveel
>

Okay, thanks Mark