Date Difference based on a column filter

[mgaut341]

I was able to get my date difference custom column, however I need it to take into account the type of service provided if there are multiple chart numbers. 

My current formula is:

Wait Times = DATEDIFF('CCHHS Mammo'[Date Referred], 'CCHHS Mammo'[Appointment],MONTH)

However, it is providing a date difference for chart number 23549 diagnostic service even though it doesnt have an appt date, since it is taking the appt date from 23549 US Breast service.

How should I fix my formula to incorporate the service being provided?

[mgaut341]

Thank you! 

[bhanu_gautam · Accepted solution]

@mgaut341 , Try using

Wait Times =
IF('CCHHS Mammo'[Service] = "Diagnostic",
DATEDIFF('CCHHS Mammo'[Date Referred], 'CCHHS Mammo'[Appointment], MONTH),
IF('CCHHS Mammo'[Service] = "US Breast",
DATEDIFF('CCHHS Mammo'[Date Referred], 'CCHHS Mammo'[Appointment], MONTH),
NULL
)
)