Hi Hui,
I'm glad I could challenge the Ninja with my question! Usually I can do just about anything in Excel, but this had me stumped. Surprisingly in all my years of scouring the web for complicated Excel ideas, I've never came across this site. Now, I think it'll be the first place I go...
I have data similar to the following:
4/02/2011 abc
4/03/2011 xyz
4/03/2011 abc
4/10/2011 abc
4/11/2011 xyz
4/13/2011 qrs
I want to have static date ranges, use one formula to drag down the 'Unique' column:
Start End Unique
4/01/2011 4/07/2011 2
4/08/2011 4/14/2011 3
So...