My bookkeepers have asked me to provide some monthly summary data from our homegrown order database system. I'm not exactly sure how to architect this.

The report they want would summarize the Quantity, Gross and Net Revenue for each SKU we sell. Each row in what is essentially a spreadsheet represents one of our SKUs, then each column gives the Quantity, etc.

Have a line item table that contains all line items for all sales.

How do I set this up? I imagine I'm building Summary fields in either a new table or in a self-join to the Line Item table, but that infant thought is as far as I'm getting. -)

I appreciate your advice.

So a search for +subsummary and you will come across many posts with samples of how to do this. The report will be based off your current found set, so you would need to find all the records for that month first and work with that found set of records. You could group by SKU.