I'm no pro at subsummary reports, but that is what you're after.
You seem to be looking for a subsummary report, sorted by articles, on a found set of invoices.
This post is simply to give you the key words to search this forum and FMP help.
it will be another more versed in setting up these reports who can answer the detail questions you run into...
hope this helps
Check out Summary Reports and Sub-Summary parts.
You can create a layout based on your invoices line items (you do have your invoiced items in a portal of related line item records don't you?).
You can create a list view report and add a sub-summary "when sorted by" your item ID field. (The sorting does your grouping BTW.)
Place all your line item fields you want for your report in this part--include a summary field to total up your quantities.
Delete the body part from your layout.
Now if you perform a find for the invoices you want and then sort the resulting found set as required for you sub-summary part, you'll get your report.
First of all thanks for the quick response.
Now I have been able to set up a report with the total amounts grouped by article but I'm still struggeling with the sub-set of invoices I only want to show.
What do you mean with perform a find?
You can perform a find by hand or in a script to restrict a report to data from a specific group of records.
Either way, you enter find mode, enter criteria (like a date or range of invoice numbers), find the records and then sort them (so that the sub-summary parts appear).
There's a lot of different ways to do this depending on your specific needs.