diff --git a/dbms/src/Storages/StorageReplicatedMergeTree.cpp b/dbms/src/Storages/StorageReplicatedMergeTree.cpp
index 13045302c4e..8ded9c49f96 100644
--- a/dbms/src/Storages/StorageReplicatedMergeTree.cpp
+++ b/dbms/src/Storages/StorageReplicatedMergeTree.cpp
@@ -1889,8 +1889,9 @@ BlockOutputStreamPtr StorageReplicatedMergeTree::write(ASTPtr query)
 		throw Exception("Table is in read only mode", ErrorCodes::TABLE_IS_READ_ONLY);
 
 	String insert_id;
-	if (ASTInsertQuery * insert = typeid_cast<ASTInsertQuery *>(&*query))
-		insert_id = insert->insert_id;
+	if (query)
+		if (ASTInsertQuery * insert = typeid_cast<ASTInsertQuery *>(&*query))
+			insert_id = insert->insert_id;
 
 	return new ReplicatedMergeTreeBlockOutputStream(*this, insert_id);
 }