From 67895da179ddda6b4056ef127473fc0a0ecfc318 Mon Sep 17 00:00:00 2001
From: Aaron Seigo <aseigo@kde.org>
Date: Fri, 20 Jun 2025 19:42:05 +0200
Subject: [PATCH 1/2] implement support for count(_, :distinct)

---
 lib/ecto/adapters/sqlite3/connection.ex                   | 4 ++++
 test/ecto/adapters/sqlite3/connection/aggregates_test.exs | 8 ++++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/ecto/adapters/sqlite3/connection.ex b/lib/ecto/adapters/sqlite3/connection.ex
index c2e27ec..fd6dd67 100644
--- a/lib/ecto/adapters/sqlite3/connection.ex
+++ b/lib/ecto/adapters/sqlite3/connection.ex
@@ -1437,6 +1437,10 @@ defmodule Ecto.Adapters.SQLite3.Connection do
 
   defp expr({:count, _, []}, _sources, _query), do: "count(*)"
 
+  defp expr({:count, _, [expr, :distinct]}, sources, query) do
+    ["count(distinct ", expr(expr, sources, query), ")"]
+  end
+
   defp expr({:count, _, [{:&, _, [_]}]}, _sources, query) do
     raise Ecto.QueryError,
       query: query,
diff --git a/test/ecto/adapters/sqlite3/connection/aggregates_test.exs b/test/ecto/adapters/sqlite3/connection/aggregates_test.exs
index 2aa1a11..e8daa98 100644
--- a/test/ecto/adapters/sqlite3/connection/aggregates_test.exs
+++ b/test/ecto/adapters/sqlite3/connection/aggregates_test.exs
@@ -28,13 +28,13 @@ defmodule Ecto.Adapters.SQLite3.Connection.AggregatesTest do
     end
   end
 
-  test "raises when trying to distinct count" do
-    assert_raise Ecto.QueryError, fn ->
+  test "distinct counts" do
+    query =
       Schema
       |> select([r], count(r.x, :distinct))
       |> plan()
-      |> all()
-    end
+
+    assert ~s{SELECT count(distinct s0."x") FROM "schema" AS s0} == all(query)
   end
 
   test "allows naked count" do

From 64ba71ade3f200fc4f06a7db46fe6e727889b35a Mon Sep 17 00:00:00 2001
From: Aaron Seigo <aseigo@kde.org>
Date: Fri, 20 Jun 2025 22:22:53 +0200
Subject: [PATCH 2/2] enable count distinct integration tests

---
 integration_test/test_helper.exs | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/integration_test/test_helper.exs b/integration_test/test_helper.exs
index 1805346..a5dd7b9 100644
--- a/integration_test/test_helper.exs
+++ b/integration_test/test_helper.exs
@@ -124,9 +124,6 @@ excludes = [
   :selected_as_with_order_by_expression,
   :selected_as_with_having,
 
-  # Distinct with options not supported
-  :distinct_count,
-
   # SQLite does not support anything except a single column in DISTINCT
   :multicolumn_distinct,