From b5c9be75c4b4784656965da2acc29e479b396a4c Mon Sep 17 00:00:00 2001
From: Nikolai Kochetov <nik-kochetov@yandex-team.ru>
Date: Mon, 12 Aug 2019 21:00:41 +0300
Subject: [PATCH] Materialize constant keys in header.

---
 dbms/src/Interpreters/InterpreterSelectQuery.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dbms/src/Interpreters/InterpreterSelectQuery.cpp b/dbms/src/Interpreters/InterpreterSelectQuery.cpp
index 2f51b596721..8e01d9b5209 100644
--- a/dbms/src/Interpreters/InterpreterSelectQuery.cpp
+++ b/dbms/src/Interpreters/InterpreterSelectQuery.cpp
@@ -452,7 +452,7 @@ Block InterpreterSelectQuery::getSampleBlockImpl()
         Block res;
 
         for (auto & key : key_names)
-            res.insert(header.getByName(key).cloneEmpty());
+            res.insert({nullptr, header.getByName(key).type, key});
 
         for (auto & aggregate : aggregates)
         {