There are probably some approaches / solutions to your request.
I think your problem might be similar to the problem here, instead of tickets with Open/Close date, the task there was to calculate attendance between StartTime and EndTime:
Hope this helps,
Close - given me some idea's but no cigar. Their ID could be a 'ticket' number but I don't want to see the 'backlog' wrapped over the same time period.
I was thinking more along the lines of putting Date as a Column and then ticket numbers across putting a '1' in the ticket column each day/date the ticket was open. I would then be able to do a sum on the date giving me the total open tickets.
How would I go about auto generating ticket column numbers for existing tickets only?
I think I am missing something on your request, I think the referenced solution should possibly serve you to.
Maybe more like Rob or John suggested here?
Could you maybe post a small example of how you would like your results to be displayed?