diff --git a/model/SqlCriteria.php b/model/SqlCriteria.php
index 65b6f58..3c0649e 100644
--- a/model/SqlCriteria.php
+++ b/model/SqlCriteria.php
@@ -147,7 +147,10 @@ class SqlCriteria
      */
     public function select($fields)
     {
-        $fields = array_map(function($item){return trim($item);},explode(',', $fields));
+        if (!is_array($fields)) {
+            $fields = explode(',', $fields);
+        }
+        $fields = array_map(function($item){return trim($item);},$fields);
         $this->select = array_merge($this->select,$fields);
         return $this;
     }