diff --git a/webtul/db.py b/webtul/db.py
index <HASH>..<HASH> 100644
--- a/webtul/db.py
+++ b/webtul/db.py
@@ -103,7 +103,10 @@ class MySQL:
             if not isinstance(param, list) and not isinstance(param, tuple):
                 param = (param,)
             cursor = self.conn.cursor()
-            ret = cursor.execute(sql, param)
+            if param is not ():
+                ret = cursor.execute(sql, param)
+            else:
+                ret = cursor.execute(sql)
             res = cursor.fetchall()
             cursor.close()
             return ret, res
fix a bug that sql statement have %s or %s and so on, that it doesn't work