// QueryAndChart — rolling 12-month total measures
// Paste into Power BI Desktop: Modeling > New measure, one measure at a time.
// Tables: Sales (Month, Category, Units, Revenue), Calendar (Date).
// Relationship: Calendar[Date] (one) to Sales[Month] (many), single direction.
Total Sales = SUM ( Sales[Revenue] )

Rolling 12M Sales =
CALCULATE (
    [Total Sales],
    DATESINPERIOD (
        Calendar[Date],
        MAX ( Calendar[Date] ),
        -12,
        MONTH
    )
)

Rolling 12M Monthly Average =
DIVIDE (
    [Rolling 12M Sales],
    12
)