From 8343cf3578c7818a5123f35d3ed3580cae3a99c8 Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Fri, 16 Jun 2017 21:05:45 +0300
Subject: [PATCH] Fixed error with NULLs [#CLICKHOUSE-2993].

---
 dbms/src/Columns/ColumnConst.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/dbms/src/Columns/ColumnConst.cpp b/dbms/src/Columns/ColumnConst.cpp
index 341140be115..c4bb27057bd 100644
--- a/dbms/src/Columns/ColumnConst.cpp
+++ b/dbms/src/Columns/ColumnConst.cpp
@@ -32,8 +32,10 @@ ColumnPtr ColumnConst<Null>::convertToFullColumn() const
     ColumnPtr nested_col;
 
     if (data_type)
-        nested_col = data_type->createConstColumn(
-            s, typeid_cast<const DataTypeNullable &>(*data_type).getNestedType()->getDefault())->convertToFullColumnIfConst();
+    {
+        const IDataType & nested_data_type = *typeid_cast<const DataTypeNullable &>(*data_type).getNestedType();
+        nested_col = nested_data_type.createConstColumn(s, nested_data_type.getDefault())->convertToFullColumnIfConst();
+    }
     else
         nested_col = std::make_shared<ColumnUInt8>(s, 0);