What is the additional if statement that will return the first-non zero value from previous row?

[ironboy0418]

I am currently doing a COVID-19 reports/dashboard through Power BI. I have this dax formula that will return the new cases for each day. However, the problem with this formula is that I am not able to return the value of the first case - it returns 0. May I ask for suggestion on how to make this formula return the value of first case as well?

Datasource: https://github.com/CSSEGISandData/COVID-19/blob/master/csse_covid_19_data/csse_covid_19_time_series/...

Source code:

New_Cases = 
VAR Countries = ConfirmedCases[Country/Region]
VAR State = ConfirmedCases[Province/State]
VAR dates = ConfirmedCases[Date]
VAR PrevDay =
CALCULATE(
    MAX(ConfirmedCases[Cases]),
    FILTER('ConfirmedCases',
    ConfirmedCases[Country/Region]=Countries && ConfirmedCases[Province/State]=State && ConfirmedCases[Date]<dates))
RETURN
IF(PrevDay=0,0,
IF(PrevDay>[Cases],0,
IF(PrevDay>0,[Cases]-PrevDay)))

Here is the current output: 

[ironboy0418 · Accepted solution]

We got the answer! Sharing the appropriate solution:

New_Cases =

VAR Countries = Confirmed_Cases[Country/Region]

VAR State = Confirmed_Cases[Province/State]

VAR dates = Confirmed_Cases[Date]

VAR tbl =   FILTER('Confirmed_Cases',

    Confirmed_Cases[Country/Region]=Countries && Confirmed_Cases[Province/State]=State && Confirmed_Cases[Date]<dates)

VAR PrevDay =

CALCULATE(

    MAX(Confirmed_Cases[Cases]),

     tbl)

RETURN

[Cases] - PrevDay

[amitchandak]

@ironboy0418 , Previous date when cases were 0 (New column)

New_Cases =
VAR Countries = ConfirmedCases[Country/Region]
VAR State = ConfirmedCases[Province/State]
VAR dates = ConfirmedCases[Date]
VAR PrevDay =
CALCULATE(
MAX(ConfirmedCases[dates]),
FILTER('ConfirmedCases',
ConfirmedCases[Country/Region]=Countries && ConfirmedCases[Province/State]=State && ConfirmedCases[Date]<dates && ConfirmedCases[New_Cases]=0))
RETURN
PrevDay

1st date when case were 0

New_Cases =
VAR Countries = ConfirmedCases[Country/Region]
VAR State = ConfirmedCases[Province/State]
VAR dates = ConfirmedCases[Date]
VAR PrevDay =
CALCULATE(
Min(ConfirmedCases[dates]),
FILTER('ConfirmedCases',
ConfirmedCases[Country/Region]=Countries && ConfirmedCases[Province/State]=State && ConfirmedCases[Date]<dates && ConfirmedCases[New_Cases]=0))
RETURN
PrevDay

[ironboy0418]

Thanks amitchandak! Do I need to create two columns for these?