Add a testcase for RANGE-type frames and NULL values

mysql-test/r/win.result

@@ -1086,3 +1086,35 @@ and 0.1 following)
 1.220	2
 3.330	1
 drop table t1;
+# 
+# RANGE-type frames and NULL values 
+# 
+create table t1 (
+pk int,
+a int,
+b int
+);
+insert into t1 values (1, NULL,1);
+insert into t1 values (2, NULL,1);
+insert into t1 values (3, NULL,1);
+insert into t1 values (4, 10 ,1);
+insert into t1 values (5, 11 ,1);
+insert into t1 values (6, 12 ,1);
+insert into t1 values (7, 13 ,1);
+insert into t1 values (8, 14 ,1);
+select 
+pk, a, 
+count(b) over (order by a 
+range between 2 preceding 
+and 2 following) as CNT
+from t1;
+pk	a	CNT
+1	NULL	3
+2	NULL	3
+3	NULL	3
+4	10	3
+5	11	4
+6	12	5
+7	13	4
+8	14	3
+drop table t1;

mysql-test/t/win.test

@@ -637,3 +637,30 @@ select
 from t1;
 
 drop table t1;
+
+--echo # 
+--echo # RANGE-type frames and NULL values 
+--echo # 
+create table t1 (
+ pk int,
+ a int,
+ b int
+);
+
+insert into t1 values (1, NULL,1);
+insert into t1 values (2, NULL,1);
+insert into t1 values (3, NULL,1);
+insert into t1 values (4, 10 ,1);
+insert into t1 values (5, 11 ,1);
+insert into t1 values (6, 12 ,1);
+insert into t1 values (7, 13 ,1);
+insert into t1 values (8, 14 ,1);
+
+
+select 
+ pk, a, 
+ count(b) over (order by a 
+                range between 2 preceding 
+                          and 2 following) as CNT
+from t1;
+drop table t1;