Retrieving Distinct Records

Hi Experts,
One of my teammate is struck with a requirement. Thought of asking suggestions from Community Experts.

In Scripting, I need to get the Count of distict Service Id from Assets belonging to particular Owner Account.

Say for example I am using Asset Mgmt - Asset BO and Asset Mgmt - Asset BC.

If the data present is as follows:

SERIAL_NUM       OWNER_ACCNT_ID
  04421313                 1-RJKL2
  04421313                 1-RJKL2
  04421313                 1-RJKL2
  04421313                 1-RJKL2
  04492398                 1-RJKL2
  04492398                 1-RJKL2
  04492398                 1-RJKL2
  04428372                 1-RJKL2
  04428372                 1-RJKL2
  04428372                 1-RJKL2

Then the count should be 3, as we have only 3 distinct SERIAL_NUM (Service Id in BC). To get the Count I can use CountRecords().