Why does COUNTROWS return EMPTY when it should return 0?

[webportal]

Why does this calculated column return an empty value, for rows that are equal to zero?

Number of Rows = 
VAR ThisIndex = 'Table'[Index]
RETURN
COUNTROWS(
    FILTER('OtherTable', 'OtherTable'[col] = ThisIndex)
) 

[amitchandak · Accepted solution]

@webportal , for no rows it will return blank, you can add +0 if needed

Number of Rows = 
VAR ThisIndex = 'Table'[Index]
RETURN
COUNTROWS(
    FILTER('OtherTable', 'OtherTable'[col] = ThisIndex)
) +0