diff --git a/activerecord/lib/arel.rb b/activerecord/lib/arel.rb
index 75333d49f6d8912318a2b724311aa4241d46f09a..6263ef42adb3360c1d55ada019605f65a46c10ff 100644
--- a/activerecord/lib/arel.rb
+++ b/activerecord/lib/arel.rb
@@ -53,7 +53,7 @@ def self.fetch_attribute(value, &block) # :nodoc:
          Arel::Nodes::GreaterThan, Arel::Nodes::GreaterThanOrEqual
       if value.left.is_a?(Arel::Attributes::Attribute)
         yield value.left
-      else
+      elsif value.right.is_a?(Arel::Attributes::Attribute)
         yield value.right
       end
     when Arel::Nodes::Or
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 687e98fe0d7dfc12a77b67d1fd2b161f43d227a0..6d22c0be283567b29e5a585e3b817e4c102f5542 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -2050,6 +2050,18 @@ def test_unscope_specific_where_value
     assert_equal 1, posts.unscope(where: :body).count
   end
 
+  def test_unscope_with_arel_sql
+    posts = Post.where(Arel.sql("'Welcome to the weblog'").eq(Post.arel_attribute(:title)))
+
+    assert_equal 1, posts.count
+    assert_equal Post.count, posts.unscope(where: :title).count
+
+    posts = Post.where(Arel.sql("posts.title").eq("Welcome to the weblog"))
+
+    assert_equal 1, posts.count
+    assert_equal 1, posts.unscope(where: :title).count
+  end
+
   def test_unscope_grouped_where
     posts = Post.where(
       title: ["Welcome to the weblog", "So I was thinking", nil]