diff --git a/src/Analyzer/HashUtils.h b/src/Analyzer/HashUtils.h
index b6d563a023e..46222755938 100644
--- a/src/Analyzer/HashUtils.h
+++ b/src/Analyzer/HashUtils.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <Analyzer/IQueryTreeNode.h>
 
 namespace DB