diff --git a/src/Storages/transformQueryForExternalDatabase.cpp b/src/Storages/transformQueryForExternalDatabase.cpp
index ac1187ba0e2..b79a5edee1d 100644
--- a/src/Storages/transformQueryForExternalDatabase.cpp
+++ b/src/Storages/transformQueryForExternalDatabase.cpp
@@ -181,7 +181,7 @@ bool removeUnknownSubexpressions(ASTPtr & node, const NameSet & known_names)
     if (const auto * ident = node->as<ASTIdentifier>())
         return known_names.contains(ident->name());
 
-    if (const auto * lit = node->as<ASTLiteral>())
+    if (node->as<ASTLiteral>() != nullptr)
         return true;
 
     auto * func = node->as<ASTFunction>();