Problem with sum _

im working on this data set :
Novel Corona Virus 2019 Dataset | Kaggle
and what i want is : The total number of confirmed cases per province or, when not
available, by country .

Can you help me ?
i tried this , but isnt right because in this case i cant do the SUM

Select SUM (Confirmed),Province_State,Country_Region
from world_health_i1160437.covid_19
Group by Province_State,Country_Region

Try grouping by the result of a CASE statement that computes the province, or if that IS NULL, the country.

i think the sum doest work because the number of confirmed cases is cumulative
for example, in the day 1 there are 20 cases and in the day 2 there are 30. it means that there are (20+10) cases in total

To do running totals in SQL, window functions are typically the best way to calculate them. See