Merge pull request #13 from travisobregon/master

Fixes #12

Author: luisdalmolin

src/Mixins/JoinRelationship.php

@@ -188,7 +188,9 @@ public function orderByUsingJoins()
 
             $this->joinRelationship(implode('.', $relationships));
 
-            $latestRelationshipModel = $this->getModel()->$latestRelationshipName()->getModel();
+            $latestRelationshipModel = array_reduce($relationships, function ($model, $relationshipName) {
+                return $model->$relationshipName()->getModel();
+            }, $this->getModel());
 
             if ($aggregation) {
                 $this->selectRaw(

tests/OrderByTest.php

@@ -34,17 +34,17 @@ public function test_order_by_relationship()
     public function test_order_by_nested_relationship()
     {
         // just making sure the query doesn't throw any exceptions
-        User::orderByUsingJoins('posts.comments.approved', 'desc')->get();
+        User::orderByUsingJoins('posts.category.title', 'desc')->get();
 
-        $query = User::orderByUsingJoins('posts.comments.approved', 'desc')->toSql();
+        $query = User::orderByUsingJoins('posts.category.title', 'desc')->toSql();
 
         $this->assertStringContainsString(
             'select "users".* from "users"',
             $query
         );
 
         $this->assertStringContainsString(
-            'order by "comments"."approved" desc',
+            'order by "categories"."title" desc',
             $query
         );
     }