diff --git a/source/application/common/dm/Dm.php b/source/application/common/dm/Dm.php
index 5f598b1..9373b9d 100644
--- a/source/application/common/dm/Dm.php
+++ b/source/application/common/dm/Dm.php
@@ -134,15 +134,19 @@ class Dm
      * @param string $fields       // 查询字段
      * @param string $order        // 查询排序
      * @param string $limit        // 查询条数
+     * @param string $group        // 查询分组
      * @return array               // 返回数组
      */
-    public function select($table, $where = null, $fields = '*', $order = null, $limit = null)
+    public function select($table, $where = null, $fields = '*', $order = null, $limit = null, $group = null)
     {
         $tableName = $this->splitTableName($table);
         $sql = 'SELECT '.$fields.' FROM '.$tableName;
         if ($where != null) {
             $sql .= ' WHERE '.$where;
         }
+        if ($group != null) {
+            $sql .= ' GROUP BY '.$group;
+        }
         if ($order != null) {
             $sql .= ' ORDER BY '.$order;
         }