What is the best way to retrieve distinct / unique values using SPQuery?

Question

I have a list that looks like:

Movie          Year
-----          ----
Fight Club     1999
The Matrix     1999
Pulp Fiction   1994

Using CA

Answer 1

After coming across post after post about how this was impossible, I've finally found a way. This has been tested in SharePoint Online. Here's a function that will get you all unique values for a column. It just requires you to pass in the list Id, View Id, internal list name, and a callback function.

function getUniqueColumnValues(listid, viewid, column,  _callback){
var uniqueVals = [];
$.ajax({
    url: _spPageContextInfo.webAbsoluteUrl + "/_layouts/15/filter.aspx?ListId={" + listid + "}&FieldInternalName=" + column + "&ViewId={" + viewid + "}&FilterOnly=1&Filter=1",
    method: "GET",
    headers: { "Accept": "application/json; odata=verbose" }
    }).then(function(response) {
        $(response).find('OPTION').each(function(a,b){
            if ($(b)[0].value) {
                uniqueVals.push($(b)[0].value);
            }
        });
        _callback(true,uniqueVals);
},function(){
    _callback(false,"Error retrieving unique column values");
});

}