Assume the following sheet, with columns titles Color, Yesterday, Today

Blue 5 7
Blue 0 9
Red 3 9

It is filtered using an autofilter on Color, and I need to show the total
for Today, but I need to exclude rows with a 0 value in the Yesterday column.

For instance, when filtered on Blue, I need to get 7

I realize I can use SUBTOTAL to get the sum of the C column across the
filtered rows, how do I exclude rows with a 0 value in column B from the
SUBTOTAL ?