From 3d3faf8dde9309307aa3818609f5706e5f8bbc8a Mon Sep 17 00:00:00 2001
From: Aidan Haran <aidanharan@yahoo.com>
Date: Mon, 6 Apr 2020 15:46:49 +0100
Subject: [PATCH] Subqueries cannot include ordering unless TOP/LIMIT also
 specified

---
 lib/arel/visitors/sqlserver.rb         | 18 ++++++++++++++
 test/cases/in_clause_test_sqlserver.rb | 34 ++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 test/cases/in_clause_test_sqlserver.rb

diff --git a/lib/arel/visitors/sqlserver.rb b/lib/arel/visitors/sqlserver.rb
index c5f2d6913..29dd5daba 100644
--- a/lib/arel/visitors/sqlserver.rb
+++ b/lib/arel/visitors/sqlserver.rb
@@ -127,6 +127,19 @@ def visit_Arel_Nodes_OuterJoin o, collector
         visit o.right, collector
       end
 
+      # Need to remove ordering from subqueries unless TOP/OFFSET also used. Otherwise, SQLServer
+      # returns error "The ORDER BY clause is invalid in views, inline functions, derived tables,
+      # subqueries, and common table expressions, unless TOP, OFFSET or FOR XML is also specified."
+      def collect_in_clause(left, right, collector)
+        if Array === right
+          right.each { |node| remove_invalid_ordering_from_in_clause(node) }
+        else
+          remove_invalid_ordering_from_in_clause(right)
+        end
+
+        super
+      end
+
       # SQLServer ToSql/Visitor (Additions)
 
       def visit_Arel_Nodes_SelectStatement_SQLServer_Lock collector, options = {}
@@ -219,6 +232,11 @@ def remote_server_table_name o
         ).quoted
       end
 
+      def remove_invalid_ordering_from_in_clause(node)
+        return unless Arel::Nodes::SelectStatement === node
+
+        node.orders = [] unless node.offset || node.limit
+      end
     end
   end
 end
diff --git a/test/cases/in_clause_test_sqlserver.rb b/test/cases/in_clause_test_sqlserver.rb
new file mode 100644
index 000000000..6ec295130
--- /dev/null
+++ b/test/cases/in_clause_test_sqlserver.rb
@@ -0,0 +1,34 @@
+require 'cases/helper_sqlserver'
+require 'models/post'
+require 'models/author'
+
+class InClauseTestSQLServer < ActiveRecord::TestCase
+  fixtures :posts, :authors
+
+  it 'removes ordering from subqueries' do
+    authors_subquery = Author.where(name: ['David', 'Mary', 'Bob']).order(:name)
+    posts = Post.where(author: authors_subquery)
+
+    assert_includes authors_subquery.to_sql, "ORDER BY [authors].[name]"
+    assert_not_includes posts.to_sql, "ORDER BY [authors].[name]"
+    assert_equal 10, posts.length
+  end
+
+  it 'does not remove ordering from subquery that includes a limit' do
+    authors_subquery = Author.where(name: ['David', 'Mary', 'Bob']).order(:name).limit(2)
+    posts = Post.where(author: authors_subquery)
+
+    assert_includes authors_subquery.to_sql, "ORDER BY [authors].[name]"
+    assert_includes posts.to_sql, "ORDER BY [authors].[name]"
+    assert_equal 7, posts.length
+  end
+
+  it 'does not remove ordering from subquery that includes an offset' do
+    authors_subquery = Author.where(name: ['David', 'Mary', 'Bob']).order(:name).offset(1)
+    posts = Post.where(author: authors_subquery)
+
+    assert_includes authors_subquery.to_sql, "ORDER BY [authors].[name]"
+    assert_includes posts.to_sql, "ORDER BY [authors].[name]"
+    assert_equal 8, posts.length
+  end
+end