Average based on multiple conditions

Ok, as per the attached file I have the following problem.

I have a No of an item, that ranges between 1-40000 or more, a value for the item (let's say price change) and a full date (8 digits as in yearmonthday). I have separated the full date into year, month and quarter.

What I want to do is to sum the price values by quarter and by No of item. The reason why I want to do this is because I have a few spreadsheets of around 700,000 rows each and I want to reduce the number of rows so that I can handle it in one spreadsheet (and then use a pivot-table or something else for further calculations).

Can you suggest a way (if there is a macro even better) to sum the prices, by quarter and by item number as well?

Thanks for any reply.

EDIT: An alternative solution would be if it is possible to create a pivot-table that reads source data from multiple workbooks (or worksheets). How can I do that?

Maybe like this:

Please Login or Register  to view this content.

The formula in I3 and copied across and down is

=SUMPRODUCT( ($A$2:$A$38=$H3) * ($D$2:$D$38=I$1) * ($F$2:$F$38=I$2), $C$2:$C$38)

Or, in list form,

Please Login or Register  to view this content.

K7 and down =SUMPRODUCT( ($A$2:$A$38=H7) * ($D$2:$D$38=I7) * ($F$2:$F$38=J7), $C$2:$C$38)

in either case, I'd change the references to use dynamic ranges on the actual data.