I have a QML app where I am sometimes using data from a live feature service, and other times using a geodatabase that is generated from that same service. I need to get some distinct values, but there are no options in QueryParameters to select distinct features, given that only the order by and where clause parts of the sql query can be modified. When I view the table in the feature service in a web browser, it has the "Return Distinct Values" option, but I don't seem to be able to access this from within my app. I could, of course, just iterate through the table and find the values myself, but this is very slow on a large table. I know when I am dealing with a .geodatabse file, I can run my own SQLite query on it, but I don't know any way around it when connected to the feature service.
Am I out of luck, or is there a way to access this functionality.