How to subtract one more month to DATEDIFF result (only if total is 0 or greater than 0)?

[JustinDoh1]

I have following measure:

ForecastMonths = DATEDIFF(

                                                FIRSTDATE ('Table'[Survey Date]),

                                                LASTDATE ('Calendar'[Month Year]),

                                                MONTH

                                              )

I am trying to adjust the result (which comes in number of month) to one more/less month.

I would like the result to be either 91 or 89.

How do I go about doing it?

Thanks for help.

[Kedar_Pande]

@JustinDoh1 

ForecastMonths =
VAR Diff = DATEDIFF(
FIRSTDATE('Table'[Survey Date]),
LASTDATE('Calendar'[Month Year]),
MONTH
)
RETURN
IF(Diff >= 0, Diff - 1, Diff)

If this answer helped, please click Kudos or mark as Solution.
-Kedar
LinkedIn: https://www.linkedin.com/in/kedar-pande

[parry2k]

@JustinDoh1 sure here it is, change the condition as per your needs

ForecastMonths = 
VAR __Months = 
DATEDIFF(
    FIRSTDATE ('Table'[Survey Date]),
    LASTDATE ('Calendar'[Month Year]),
    MONTH
)
RETURN
IF ( __Months >= 0, __Months - 1, __Months )

[parry2k · Accepted solution]

@JustinDoh1 not sure what you are trying to achieve, when you add or subtract:

ForecastMonths = DATEDIFF(
                                                FIRSTDATE ('Table'[Survey Date]),
                                                LASTDATE ('Calendar'[Month Year]),
                                                MONTH
                                              ) + 1 // or -1

[JustinDoh1]

@parry2k Thank you and sorry.

I guess I need to use  -1.

Can I ask you one more question?

How can I wrap so that this condition only applies if value is 0 or greater than 0 so that there is no -1?

I guess I am trying to use IF statement for the result..  Thanks.

[djurecicK2]

Hi @JustinDoh1 ,

 You can use EDATE on the LASTDATE to achieve this:

https://learn.microsoft.com/en-us/dax/edate-function-dax