From 457f3b99413e50c7cf393b06a86483e1854d86c8 Mon Sep 17 00:00:00 2001
From: Igor Babaev <igor@askmonty.org>
Date: Fri, 23 Sep 2016 14:42:12 -0700
Subject: [PATCH] Added the test case for bug mdev-9941 that was fixed some
 time ago.

---
 mysql-test/r/win.result | 43 +++++++++++++++++++++++++++++++++++++++++
 mysql-test/t/win.test   | 27 ++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/mysql-test/r/win.result b/mysql-test/r/win.result
index 4d9c58cc851..233308cd031 100644
--- a/mysql-test/r/win.result
+++ b/mysql-test/r/win.result
@@ -2142,3 +2142,46 @@ pk	a	d	sum_1	sum_2
 10	2	0.800	1.700	2.400
 11	2	0.900	0.900	2.800
 drop table t1;
+#
+# MDEV-9941: two window functions with compatible partitions 
+#
+create table t1 (
+a int,
+b int,
+c int
+);
+insert into t1 values 
+(10, 1, 1),
+(10, 3, 10),
+(10, 1, 10),
+(10, 3, 100),
+(10, 5, 1000),
+(10, 1, 100);
+explain format=json
+select 
+a,b,c,
+row_number() over (partition by a),
+row_number() over (partition by a, b)
+from t1;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "window_functions_computation": {
+      "sorts": {
+        "filesort": {
+          "sort_key": "t1.a, t1.b"
+        }
+      },
+      "temporary_table": {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 6,
+          "filtered": 100
+        }
+      }
+    }
+  }
+}
+drop table t1;
diff --git a/mysql-test/t/win.test b/mysql-test/t/win.test
index 10c673ac1b3..60bd42e026a 100644
--- a/mysql-test/t/win.test
+++ b/mysql-test/t/win.test
@@ -1310,3 +1310,30 @@ select pk, a, d,
 from t1;
 
 drop table t1;
+
+--echo #
+--echo # MDEV-9941: two window functions with compatible partitions 
+--echo #
+
+create table t1 (
+  a int,
+  b int,
+  c int
+);
+ 
+insert into t1 values 
+ (10, 1, 1),
+ (10, 3, 10),
+ (10, 1, 10),
+ (10, 3, 100),
+ (10, 5, 1000),
+ (10, 1, 100);
+
+explain format=json
+select 
+  a,b,c,
+  row_number() over (partition by a),
+  row_number() over (partition by a, b)
+from t1;
+
+drop table t1;