diff --git a/src/Interpreters/join_common.cpp b/src/Interpreters/join_common.cpp
index 60f67c8a9d1..478df653f3b 100644
--- a/src/Interpreters/join_common.cpp
+++ b/src/Interpreters/join_common.cpp
@@ -127,7 +127,7 @@ bool isNullable(const DataTypePtr & type)
 /// Note: LowCardinality(T) transformed to LowCardinality(Nullable(T))
 DataTypePtr convertTypeToNullable(const DataTypePtr & type)
 {
-    if (type->isNullable())
+    if (isNullable(type))
         return type;
 
     if (const auto * low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(type.get()))