Q:

Showing last 4 values based on filter Power Bi

I have some Retirement fund data which I visualize with scatterplots and bar charts. 
I am filtering the data with a Year slicer and a quarter filter (and fund type, but this is not relevant).
In my report I have 6 visuals, 4 of which are quarterly data, and two are yearly data. 
I am using a bar chart visual to show certain values like the following:

My visual shows Quarter data for the selected Year. ( for example: it shows the invested equity per quarter for the year 2018)
However, for 2019 only 3 quarters are yet recorded. 
Is it possible (for 2019) to show 3 quarters of 2019 and the last quarter of 2018 so that my bar chart still shows 4 quarters?
If so, could i make it  so that the year is also visualized on the x axis so that one may not get confused as to what year the quarter is from? (i.e. show Q4 2018 and Q1, Q2, Q3 2019)

A:

The best option is to have a current month indicator in your calendar table, which then counts back and forward in time. This example is based on Power Query and has current month and years/quarters/months ago. So for example March would be 0, Feb would be -1 etc.
You could also use something like in DAX as a calculated column:
Months = DATEDIFF([start],[end],MONTH)

with the Start being NOW() and the end the date in your calendar table
When the report refreshes it will recalculate the months ago and filter the visual so it will always correctly show the current Nth months you select. You could also use TOP, but if the calendar has dates in the future it might return those.

The top visual displays the unfiltered visual, the bottom with the 'Months ago' of 0, -1, -2, -3

