In Microsoft Excel, in a pivot table, you can right click on the dates - while within the pivot table, on a date and select group (from the drop down menu) - then you can choose different groupings, week, month, year, etc.
Then, when in the pivot table field list, for a row or column you can choose the date by week, month, year, etc.
Anyone know if you can do this in Google Spreadsheets?
The Google site for spreadsheets only covered very basic instructions. I was going to ask there, but I found this site while searching and thought I would try here first.