Currently, when building a report with deals and sales activities, the report will contain a join of the deal properties and activity fields for each activity associated with the deal.
Since this is an inner join, any deals without activity are lost, which means that it is not possible to view deals that have none. I'd love to do a pivot table and do a sum of open tasks and a sum of overdue tasks.
But currently, I won't be able to see deals that have no tasks.