There's more than one way to set up a cross tab report and more than one way to set up tables/occurrences/relationships to support such a report. Which did you set up to do this?
And which part of the above are you not able to produce?
I have purchases table and then a sub summary report by category.
The same with invoices, but on separate report.
What I can not achieve, is either creating joint table or creating joint report. When I create joint table with via foreign key in invoices and foreign key in purchases, the values displayed are blanks.