Title says it all
As Ralf points out, this feature will be an extension to OData v4. Implementing this part of the protocol is not an immediate priority for us, but we will continue to watch the feedback on this and other channels.
I suggest waiting until http://docs.oasis-open.org/odata/odata-data-aggregation-ext/v4.0/odata-data-aggregation-ext-v4.0.html is approved.
Rob Drawsky commented
I think it should be like this:
What about full support for aggregate queries including "group by" and "having?"
Dennis Apter commented
I think it should be like this: http://community.devexpress.com/blogs/theonewith/archive/2010/08/09/odata-provider-for-xpo-summary-extensions-summary.aspx