Merge pull request #758 from aidanharan/in-clause-no-ordering

Rails 6: Subqueries cannot include ordering unless TOP/LIMIT also specified

Author: wpolicarpo

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

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