Dynamic date ranges

the pre-defined date ranges as well as own date ranges are always relative to the current date.

scenario

i want a table with visits for each month with to cols: first is value of visitors of current month, 2nd is the change to the previous month.

solution

i need a date range which is truly "last month" compared to the month item in a table. this way i could just add two cols to the table, 1st only visits, 2nd visits and time range