The new pivot tables in interfaces should give you this. In various bases we take the primary date field and then create subfields with formulas for some combo of year-month, and then we are able to use those fields  in selecting and grouping.

There's definitely a bug in the forms in the interface at the moment, we have an interface which presents a form for the add record button, but it is not the form that is available to edit when editing the interface, nor is it the form that we have s...