add some integration tests

Author: zachdaniel

integration_test/myxql/test_helper.exs

@@ -113,7 +113,9 @@ excludes = [
   # MySQL doesn't support indexed parameters
   :placeholders,
   # MySQL doesn't support specifying columns for ON DELETE SET NULL
-  :on_delete_nilify_column_list
+  :on_delete_nilify_column_list,
+  # MySQL doesnt' support anything except a single column in DISTINCT
+  :multicolumn_distinct
 ]
 
 if Version.match?(version, ">= 8.0.0") do

integration_test/sql/subquery.exs

@@ -112,4 +112,34 @@ defmodule Ecto.Integration.SubQueryTest do
               select: fragment("? + ?", p.visits, ^1)
     assert [12, 12] = TestRepo.all(query)
   end
+
+  test "subqueries in order by" do
+    TestRepo.insert!(%Post{visits: 10, title: "hello"})
+    TestRepo.insert!(%Post{visits: 11, title: "hello"})
+
+    query = from p in Post, as: :p, order_by: [asc: exists(from p in Post, where: p.visits > parent_as(:p).visits)]
+
+    assert [%{visits: 11}, %{visits: 10}] = TestRepo.all(query)
+  end
+
+  @tag :multicolumn_distinct
+  test "subqueries in distinct" do
+    TestRepo.insert!(%Post{visits: 10, title: "hello1"})
+    TestRepo.insert!(%Post{visits: 10, title: "hello2"})
+    TestRepo.insert!(%Post{visits: 11, title: "hello"})
+
+    query = from p in Post, as: :p, distinct: exists(from p in Post, where: p.visits > parent_as(:p).visits), order_by: [asc: :title]
+
+    assert [%{title: "hello"}, %{title: "hello1"}] = TestRepo.all(query)
+  end
+
+  test "subqueries in group by" do
+    TestRepo.insert!(%Post{visits: 10, title: "hello1"})
+    TestRepo.insert!(%Post{visits: 10, title: "hello2"})
+    TestRepo.insert!(%Post{visits: 11, title: "hello"})
+
+    query = from p in Post, as: :p, select: sum(p.visits), distinct: exists(from p in Post, where: p.visits > parent_as(:p).visits)
+
+    assert [20, 11] = TestRepo.all(query)
+  end
 end

integration_test/tds/test_helper.exs

@@ -57,7 +57,9 @@ ExUnit.start(
     # MSSQL can't reference aliased columns in ORDER BY expressions
     :selected_as_with_order_by_expression,
     # MSSQL doesn't support specifying columns for ON DELETE SET NULL
-    :on_delete_nilify_column_list
+    :on_delete_nilify_column_list,
+    # MySQL doesnt' support anything except a single column in DISTINCT
+    :multicolumn_distinct
   ]
 )