diff --git a/udfs/test/multimax.sql b/udfs/test/multimax.sql
index 9c68300..d870a34 100644
--- a/udfs/test/multimax.sql
+++ b/udfs/test/multimax.sql
@@ -5,14 +5,17 @@ CREATE TEMPORARY TABLE tData
 		UNION SELECT 1, 2, 20
 		UNION SELECT 1, 3, 30
 		UNION SELECT 1, 2, 21
+		UNION SELECT 1, NULL, -1
 		UNION SELECT 2, '4', 40
 		UNION SELECT 2, '6', 60
 		UNION SELECT 2, '5', 50
 		UNION SELECT 2, '5', 51
+		UNION SELECT 2, NULL, -1
 		UNION SELECT 3, 7, 70
 		UNION SELECT 3, 8, 80
 		UNION SELECT 3, 9, NULL
 		UNION SELECT 3, 8, 81
+		UNION SELECT 3, NULL, -1
 		UNION SELECT 4, NULL, 101
 		UNION SELECT 4, NULL, 102;