Hi dear

[WaelTalaat79]

I am trying to calculate a if condition for previousmonth and I got this message 

MdxScript(Model) (13, 76) Calculation error as attached photo 

[v-luwang-msft]

Hi @WaelTalaat79 ,

You have to read the fine print here to understand how PREVIOUSMONTH (and similar functions) work:

https://support.office.com/en-US/article/PREVIOUSMONTH-Function-DAX-72fb8dda-6cd6-49e6-b9b4-8a5f6324...

"This function returns all dates from the previous month, using the first date in the column used as input. For example, if the first date in the dates argument refers to June 10, 2009, this function returns all dates for the month of May, 2009."

So, mainly you have to use this in a "context aware way". Here is the example from the page:

Example

The following sample formula creates a calculated field that calculates the 'previous month sales' for the Internet sales.

To see how this works, create a PivotTable and add the fields, CalendarYear and MonthNumberOfYear, to the Row Labels area of the PivotTable. Then add a calculated field, named Previous Month Sales, using the formula defined in the code section, to the Values area of the PivotTable.

=CALCULATE(SUM(InternetSales_USD[SalesAmount_USD]), PREVIOUSMONTH('DateTime'[DateKey]))

And you could use the measure to get last month data:

lastmonth =
IF (
    MONTH ( MAX ( 'Date'[Date] ) ) = 1,
    DATE ( YEAR ( MAX ( 'Date'[Date] ) ) - 1, 12, DAY ( MAX ( 'Date'[Date] ) ) ),
    DATE ( YEAR ( MAX ( 'Date'[Date] ) ), MONTH ( MAX ( 'Date'[Date] ) ), DAY ( MAX ( 'Date'[Date] ) ) )
)

lastmon2 = IF (
    MONTH ( MAX ( 'Date'[Date] ) ) = 1,12,0
    
   
)

And you could refer:

Create a measure that shows me the previous month

Did I answer your question? Mark my post as a solution!

Best Regards

Lucien

[Fowmy]

@WaelTalaat79 

Modify your meusre as follows: 

= IF( MONTH( PREVIOUSMONTH( 'Dates'[Date].[Date] ) ) = 12 , 0 , 1 )

[WaelTalaat79]

error message MdxScript(Model) (13, 72)

= 12 mean December so should I select MonthNo instead of date

[Fowmy]

@WaelTalaat79 

Where/what are you using this measure? Please share screenshot of the calcualtion 

[WaelTalaat79]

•  this the calculated formula 
• so I need the manthly impact by subtracting  the calculated month - previous month
• but the problem in month of Jan. that considering the previous month as December that should be always Zero and the previous month fromula bring December value as normal fromula
• so I need that if the previous month is December put zero if not apply the fromula

  And this is the previous month fromula

  

   

   

[Ashish_Mathur]

Hi,

Please describe the question and show the expected result.  Share the download link of your PBI file.