Month over Month calculation

[Winniethewinner]

Hello PBI experts, 

I have a sample FactTable:

And a Month_Order table:

I'm trying to create a measure to compare Month over Month sales:

Sales last Month = 
CALCULATE(
    SUM(FactTable[Sales]),
    PARALLELPERIOD(
        Month_Order[Year/Month].[Date],
        -1,
        MONTH)
)

But I'm not sure how to correct the above DAX, and I'm getting the same value as Sum of Sales:

(on a side note - we use 10,11,12,01,02...... as month column because these are the values retrieved from our db and used to connect different tables in the real life PBI file.)

Can anyone please advise? Thanks. 

[amitchandak]

@Winniethewinner , Use date table, Marked as date table

example

Month behind Sales = CALCULATE(SUM(Sales[Sales Amount]),dateadd('Date'[Date],-1,Month))

Why Time Intelligence Fails - Powerbi 6 Savior Steps for TI :https://youtu.be/OBf0rjpp5Hw
https://amitchandak.medium.com/power-bi-5-key-points-to-make-time-intelligence-successful-bd52912a5b...
To get the best of the time intelligence function. Make sure you have a date calendar and it has been marked as the date in model view. Also, join it with the date column of your fact/s. Refer :radacad sqlbi My Video Series Appreciate your Kudos.