Crystal Reports Increment a number on max date

Message

   Hi all,

I have the follow script which increments by 1 each time a particular vehicle has been into the service department after the specified date. If the same vehicle has been in twice after this date I still only want to count it once. Hence I am trying to count the max date. At the moment my script counts each instance the vehicle has been in. 

Not sure if I am using the correct logic construct, but the existing script below nearly gives me what I need.

Existing Script

WhilePrintingRecords;
NumberVar CountService;
NumberVar CountReport;
If maximum ({service_Date},{Vehicle_Number}) > Date (2010, 06, 07) then
(CountService := CountRO + 1;
CountReport := CountReport + 1)

A snapshot of the current result looks like the following,

Service Date            Vehicle Number                  Count Service
19.04.2010              6FPAAAJG517840                        1
11.06.2010              6FPAAAJG517840                        2
24.08.2010              ABC12345891111                         3

What I am trying to achieve

Service Date            Vehicle Number                  Count Service

19.04.2010              6FPAAAJG517840                        0
11.06.2010              6FPAAAJG517840                        1
24.08.2010              ABC12345891111                          2

Any assistance would be GREATLY appreciated.

Thanks KR

Edited by keithrichards - 03 Jul 2010 at 11:36pm