Sum in Expression : For Pivot Table

[#1]

Hi,

I have a pivot table which looks like

City                    Zipcodes                    NumberOfRestaurant               Expression

                             111111                              250                              550

Rockford               111111                             300                                 550 

                            111113                              400                              600

                             111113                              200                              600

                                111111                              100                              100

indiana                   111112                              200                              200

I am looking to get the sum of each city and the zipcodes in the city.

So the answer should be as shown in the expression above

Under Expresson I tried

Sum(Total<City, Zipcodes>, NumberofRestaurant)

Any suggestions pls.

Thanks

[#2]

I think the issue could be because in my data from QVD I have the Zipcodes which are showing as "-".

this I think is giving the wrong numbers.

any suggestion in the formula given on this dicussion how can I exclude the calculations for the "-" ?

Thanks-