diff --git a/src/Storages/MySQL/MySQLHelpers.h b/src/Storages/MySQL/MySQLHelpers.h
index 3b047896eb1..712c5a2c719 100644
--- a/src/Storages/MySQL/MySQLHelpers.h
+++ b/src/Storages/MySQL/MySQLHelpers.h
@@ -1,3 +1,4 @@
+#pragma once
 #include "config_core.h"
 
 #if USE_MYSQL