newbie needs help counting summary records.

[#1]

My app as multiple records that each have revenue for one ad.  Some ads have $0 for the total revenue for the ad. I need an expression to count the ads that total Zero  and another expression to count the rest.

sample data:

ad1     cost1     5.00

ad1     cost2     0.00

ad1     cost3     6.15

ad2     cost1     0.00

ad2     cost2     0.00

ad3     cost5     8.25

results I need:  Zero $ ads = 1

                       others      = 2