DAX: Measure SUM only if Column="SomeValue"

[malw]

I've got what is I assume a simple DAX problem.

I'm trying to SUM the number of Events in my 'Events'[CurrentValue] field only when the related 'Event Type'[Event Sub Type]="Digital Calls"

I tried:

Digital Call Minutes:=CALCULATE(SUM(Event[Current Value]),FILTER(Event, 'Event Type'[Event Sub Type]="Digital Call"))

but that throws the following error:

Warning Measure 'Measure'[Digital Call Minutes] : A single value for column 'Event Sub Type' in table 'Event Type' cannot be determined. This can happen when a measure formula refers to a column that contains many values without specifying an aggregation such as min, max, count, or sum to get a single result. 

THe reason I'm doing this is because the Current Value field has multiple data types depending on the Event Sub Type - so I can't just SUM every Event Sub Type as it'll error out. All I want to do is restrict the SUM to a particular subset. I gather I'm missing something simple here!!

Edit: I should add the Event -> Event Type tables are Many to One with bi-directional filtering turned on. So each Event will have only one Event Type/SubType

[MattAllington · Accepted solution]

Your filter function is operating over the Event table (first parameter), but then you are applying a filter from the 'event type' table. Try changing the first parameter to be 'event type'

[malw]

Thanks Matt, that did the trick. I also had to change it to SUMX so I could convert the values to ints from strings.

I ended up with the following, which has worked:

Digital Call Minutes:=CALCULATE(SUMX(Event,VALUE(Event[Current Value])/60),FILTER('Event Type', 'Event Type'[Event Sub Type]="Digital Call"))