Fix GROUP BY clause for QuestDB - use full expressions instead of aliases

dashboard/server.py

@@ -137,9 +137,9 @@ async def get_analytics(
         cont_list = ",".join([f"'{c.strip()}'" for c in continents.split(",")])
         query += f" and {m_prefix}continent in ({cont_list})"
         
-    query += " group by label"
+    query += f" group by {selected_group}"
     if sub_group_by and sub_group_by in groups_map:
-        query += ", sub_label"
+        query += f", {groups_map[sub_group_by]}"
     
     query += " order by label asc"