Input Mask on Date for Year or Month Only

I want to have either a single classification for Year-Month, or a field for
year, and a field for Month.

I'd like to be able to use the Date/Time functions to compare these to other
data.

Can I use an input mask to caputre only the year or only the month?

Specifically for the month, I'd like the user to be able to enter "August"
or "08" into the field - not sure how to do this if I used "Integer" or
"Text" as the field type.

If anyone has some thoughts on this, they'd be much appreciated.

Thanks;
Ben.
.