Dynamic user selected date comparison variance calculations

Jacinta

I am seeking support on ideas for the best way to allow a user to manually select one date span and then select a second date span for comparison, so that the visuals show the variance of $'s as well as % from the first time span selected and the second date span selected.

The user does not want pre built time span variance calculations they want to be able to explore any dates from this year and last year and see the variance. Whether its between yesterday and the day before, or from yesterday to same day last year.

Thanks for any thoughts and ideas.