[Update 15 May 2011: see this posting for additional information about this technique.]
Demo file: 2010-11-21-count-unique.zip (requires FM 10 or later)
A question that comes up regularly on various FileMaker forums is some variation on “I have a table of sales data for my organization. For a given found set within that table, it’s easy to produce a report grouped by salesperson showing number of sales, total sales amount, etc…
…and at the bottom of the report, I can easily display grand totals for number of sales and total sales amount…
