How to dynamically retrieve last months data

[semidevil]

I’m trying to create a bar chat that will always refresh to the previous month’s data, but keep the bar chart for previous year the same.

My bar chat will have 4 bars: 2015 bar, which will always display data for 201512(dec 2015), 2016 bar which will display 201612(dec 2016), 2017bar which for 201712(dec 2017), and a 2018 bar which will always change( so in February, it should automatically update to Jan 2018).

What would be the best way to start doing this?

 

[gazpage]

Something like this.

LastMonth = 
IF (
    MONTH ( TODAY () ) = 1,
    BLANK(),
    CALCULATE (
        [TotalValue],
        FILTER (
            Data,
            Data[Year] = YEAR ( TODAY() )
                && Data[Month] = MONTH( TODAY() ) - 1
        )
    )
)

and

Graph = 
IF (
    VALUES ( Data[Year] ) = YEAR ( TODAY () ),
    [LastMonth],
    [TotalValue]
)

Depending on the structure of your calendar table you might be able to simplify (ie if you had a unique month identifier column).