Datediff using a specific ID

[Dan492813]

I'm trying to use the completed date of action "C1001A" to find out the age of the subsiquent actions in days. 

I think the formula I'm using is filtering everything except "C1001A" out though. 

Holding stage age  =

VAR startdate = CALCULATE(MAX(hgmcntac[completed_dt]), hgmcntac[action_cd] = "C1001A")

RETURN

CALCULATE(DATEDIFF(startdate,TODAY(), DAY))

I want to end up with:  x number of days since completion of action "C1001A"

Thanks in advance.

[Greg_Deckler · Accepted solution]

@Dan492813 Maybe:

Holding stage age  =
VAR startdate = MAXX(FILTER('hgmcntac', hgmcntac[action_cd] = "C1001A"), hgmcntac[completed_dt])
RETURN
 (TODAY() - startdate) * 1.

[Dan492813]

@Greg_Deckler  Thank you very much