Hi Milica,
A simple way of getting a count of the rows is to use the GetDatasourceRow() expression:
NumberOfResults:=GetDataSourceRow("string DatasourceName","string FilterName","Boolean returnRowCount","Boolean refresh");
set the third parameter to
"True"
to return the number of results for the specified filter.
Could you please provide more information on what you are trying to do with Sandbox integrations?
Thanks
Keiran