Schedule count by shift and date...

thank you for your reply but this is not what i want...
let me give you an example...
for employee with id 200791 at Aug 13 2012 his first assigned task starts at 12:00 am (cell L2) and his last assigned task ends at 08:00 pm (cell N8). Therefore his shift is 12:00 to 20:00 and that counts for 1 schedule at Aug 13th for shift 12:00-20:00.
So what i need first is to find for every unique id and for the date range i have (13/08/12-19/08/12) the earliest start time (minimum value in column L with criteria the id and the date) and the latest stop time (max value in column N with criteria the id and the date).
Then I will find all the unique shifts and count them for every different date (... and that is the easy part )

I hope i made my task more clear...

Any other ideas?
please for your help!