Add ability to order by fields other than timestamp for aggregation entities

graph/src/schema/api.rs

@@ -493,6 +493,12 @@ fn add_types_for_aggregation_types(
     input_schema: &InputSchema,
 ) -> Result<(), APISchemaError> {
     for (name, agg_type) in input_schema.aggregation_types() {
+        // Combine regular fields and aggregate fields for ordering
+        let mut all_fields = agg_type.fields.to_vec();
+        for agg in agg_type.aggregates.iter() {
+            all_fields.push(agg.as_agg_field());
+        }
+        add_order_by_type(&mut api.document, name, &all_fields)?;
         add_aggregation_filter_type(api, name, agg_type)?;
     }
     Ok(())
@@ -686,13 +692,25 @@ impl FilterOps {
                     s::Type::NamedType("OrderDirection".to_string()),
                 ),
             ],
-            FilterOps::Aggregation => vec![input_value(
-                "interval",
-                "",
-                s::Type::NonNullType(Box::new(s::Type::NamedType(
-                    "Aggregation_interval".to_string(),
-                ))),
-            )],
+            FilterOps::Aggregation => vec![
+                input_value(
+                    "interval",
+                    "",
+                    s::Type::NonNullType(Box::new(s::Type::NamedType(
+                        "Aggregation_interval".to_string(),
+                    ))),
+                ),
+                input_value(
+                    "orderBy",
+                    "",
+                    s::Type::NamedType(format!("{}_orderBy", type_name)),
+                ),
+                input_value(
+                    "orderDirection",
+                    "",
+                    s::Type::NamedType("OrderDirection".to_string()),
+                ),
+            ],
         };
 
         let mut args = vec![skip, first];

graph/src/schema/input/mod.rs

@@ -824,7 +824,7 @@ impl Aggregate {
 
     /// The field needed for the finalised aggregation for hourly/daily
     /// values
-    fn as_agg_field(&self) -> Field {
+    pub fn as_agg_field(&self) -> Field {
         Field {
             name: self.name.clone(),
             field_type: self.field_type.clone(),

graphql/src/store/prefetch.rs

@@ -713,8 +713,8 @@ impl<'a> Loader<'a> {
             // that causes unnecessary work in the database
             query.order = EntityOrder::Unordered;
         }
-        // Aggregations are always ordered by (timestamp, id)
-        if child_type.is_aggregation() {
+        // Apply default timestamp ordering for aggregations if no custom order is specified
+        if child_type.is_aggregation() && matches!(query.order, EntityOrder::Default) {
             let ts = child_type.field(kw::TIMESTAMP).unwrap();
             query.order = EntityOrder::Descending(ts.name.to_string(), ts.value_type);
         }