评价逻辑

@@ -331,10 +331,12 @@ class Course extends Api
 
         $star = $star1+$star2;
 
+        if(!empty($star)){
             foreach ($star as $key => $row) {
                 $create_time[$key] = $row['create_time'];
             }
             array_multisort($create_time, SORT_DESC, $star);
+        }
 
         $course['star'] = $star;