Group On an ISO 8601 DateTime (1997-07-16T19:20:30.45Z) in a PivotTable?

[winterminute]

I have a some server logs files that I want to slice/dice in Excel. Everything is timestamped, but I want to rollup activity into 15min chunks. For example, show me the total error count for a 15min window for the last 24 hrs. I think Grouping on the field in a PivotTable will give me just that. However, I can't. I get a generic error about can't group on that field. I think it has to do with the DateTime format my logs are in.

Example:1997-07-16T19:20:30.45Z

* Is it possible to take a list of rows group it (automatically) into 15min chunks?
* Do I need to do something special with the DateTime format to make Excel happy?

 

[Derek Brown]

You will find a possible solution at:
http://social.technet.microsoft.com/Forums/en/excel/thread/3b100f35-9c9a-41b9-b022-3a5b89d6aa7f