Current month vs Previous month

[Larry130]

Hi! Could you guys give some help? I'm struggling here.

I need to do a calculation between the current x last month, but I'll not use a date dimension to show each month in a table/graph. Because of that, the PrevMonth below is not working. What should I do to bring the last month data, so I can divide with the MTD and found the % between them?

ID Alert = COUNT('Alerts'[ID])

PrevMonth = CALCULATE([ID Alert],PARALLELPERIOD('Calendar'[Date],-1;MONTH))

Tks in advance.

[v-ljerr-msft · Accepted solution]

Hi @Larry130,

If I understand you correctly, the formula below should work in your scenario. 

PrevMonth =
VAR currentMonth =
    MONTH ( TODAY () )
VAR currentYear =
    YEAR ( TODAY () )
RETURN
    IF (
        currentMonth = 1,
        CALCULATE (
            [ID Alert],
            FILTER (
                ALL ( 'Calendar'[Date] ),
                YEAR ( 'Calendar'[Date] )
                    = currentYear - 1
                    && MONTH ( 'Calendar'[Date] ) = 12
            )
        ),
        CALCULATE (
            [ID Alert],
            FILTER (
                ALL ( 'Calendar'[Date] ),
                YEAR ( 'Calendar'[Date] ) = currentYear
                    && MONTH ( 'Calendar'[Date] )
                        = currentMonth - 1
            )
        )
    )

Regards

[mnarmeen]

Dear @v-ljerr-msft ,

I have a similar problem but the following code shows blank. My scenario is to calculate max difference between two time duration (hours) which is already a calculated column (DiffDeliveryTime). Slight difference is that I don't want to use calendar table to filter out my values instead I want to use my own table in which dates are stored. The dates are repeating as many deliveries are scheduled on the same day as well.

PrevMonth =
VAR currentMonth =
    MONTH ( invoice[DeliveryDate] )
VAR currentYear =
    YEAR ( invoice[DeliveryDate] )
RETURN
    IF (
        currentMonth = 1,
        CALCULATE (
            MAX(DiffDeliveryTime),
            FILTER (
                ALL ( invoice[DeliveryDate]),
                YEAR ( invoice[DeliveryDate] )
                    = currentYear - 1
                    && MONTH ( invoice[DeliveryDate] ) = 12
            )
        ),
        CALCULATE (
            MAX(DiffDeliveryTime),
            FILTER (
                ALL ( invoice[DeliveryDate] ),
                YEAR ( invoice[DeliveryDate] ) = currentYear
                    && MONTH ( invoice[DeliveryDate] )
                        = currentMonth - 1
            )
        )
    )

[Larry130]

PERFECT! Thanks @v-ljerr-msft

I've tried to use the SQLBI DAX Pattern for previous month, but was really hard to understand. Your way of doing it using VAR was way easier to understand. I'll study VAR!