apex.server.process("AJAX_GET_DATA",
                    {x01: apex.jQuery('#P47_SL').val()},
                    {dataType: "JSON",
                    loadingIndicator: '#P47_LT',
                    success: function(pData){
   $('#P47_LT').empty();
   for (var i = 0; i <= pData.length; i++) {
      $('#P47_LT').append('<option value="' + pData[i].ID + '">' + pData[i].FIO + '</option>');
      }
   console.log(pData);
   }
});

DECLARE
   v_json varchar(1024);
   v_json_res varchar(1024);
BEGIN
   for i in (select t.fio, t.id
             from users_data t
             where  t.id_group = apex_application.g_x01
             order by t.fio)
      loop
	     v_json := v_json||'{'||'"ID":'||i.id||','||' "FIO":"'||i.fio||'"},';
	  end loop;
	  
   v_json_res := '['||substr(v_json, 1, length(v_json) - 1)||']';
   Htp.Prn(v_json_res);
END;