From 12d24a88988c42f81261c79da98d2bf66dbcfa86 Mon Sep 17 00:00:00 2001
From: Will Townsend <will@townsend.io>
Date: Tue, 21 Jul 2026 19:52:56 -0700
Subject: [PATCH] fix(aggregates): handle offset-only aggregate queries

Problem:
Aggregate queries were wrapped only for `distinct` or `limit`. An ordered query with only an offset could therefore aggregate the wrong input set because the offset was not applied inside the aggregate subquery.

Change:
Wrap offset-only inputs in all three aggregate-query paths and preserve ordering whenever a limit or offset depends on it. Continue removing irrelevant ordering when no row-selection operator requires it.

Provenance:
This is an existing AshSQL lateral-query defect discovered while reviewing the grouped aggregate extraction. It is intentionally isolated from the grouped feature branch.
---
 lib/aggregate_query.ex | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/lib/aggregate_query.ex b/lib/aggregate_query.ex
index ad612de..9ad82f7 100644
--- a/lib/aggregate_query.ex
+++ b/lib/aggregate_query.ex
@@ -36,12 +36,12 @@ defmodule AshSql.AggregateQuery do
 
       {:ok, query} ->
         query =
-          if query.distinct || query.limit do
+          if query.distinct || query.limit || query.offset do
             query =
               query
               |> Ecto.Query.exclude(:select)
-              |> Ecto.Query.exclude(:order_by)
               |> Map.put(:windows, [])
+              |> maybe_exclude_subquery_order()
 
             from(row in subquery(query), as: ^query.__ash_bindings__.root_binding, select: %{})
           else
@@ -99,12 +99,12 @@ defmodule AshSql.AggregateQuery do
           end
 
         filtered =
-          if filtered.distinct || filtered.limit do
+          if filtered.distinct || filtered.limit || filtered.offset do
             filtered =
               filtered
               |> Ecto.Query.exclude(:select)
-              |> Ecto.Query.exclude(:order_by)
               |> Map.put(:windows, [])
+              |> maybe_exclude_subquery_order()
 
             from(row in subquery(filtered), as: ^query.__ash_bindings__.root_binding, select: %{})
           else
@@ -169,12 +169,12 @@ defmodule AshSql.AggregateQuery do
           end
 
         filtered =
-          if filtered.limit do
+          if filtered.limit || filtered.offset do
             filtered =
               filtered
               |> Ecto.Query.exclude(:select)
-              |> Ecto.Query.exclude(:order_by)
               |> Map.put(:windows, [])
+              |> maybe_exclude_subquery_order()
 
             from(row in subquery(filtered), as: ^query.__ash_bindings__.root_binding, select: %{})
           else
@@ -255,4 +255,9 @@ defmodule AshSql.AggregateQuery do
         )
     end)
   end
+
+  defp maybe_exclude_subquery_order(%{limit: nil, offset: nil} = query),
+    do: Ecto.Query.exclude(query, :order_by)
+
+  defp maybe_exclude_subquery_order(query), do: query
 end