1 files changed, 50 insertions, 0 deletions
diff --git a/mysql-test/main/join_outer.result b/mysql-test/main/join_outer.result
index 6753349dece..9245111369f 100644
--- a/mysql-test/main/join_outer.result
+++ b/mysql-test/main/join_outer.result
@@ -2460,5 +2460,55 @@ id	sid	id
 1	NULL	NULL
 2	NULL	NULL
 drop table t1, t2;
+#
+# MDEV-16726: SELECT with STRAGHT JOIN containing NESTED RIGHT JOIN
+#             converted to INNER JOIN with first constant inner table
+#
+CREATE TABLE t1 (
+pk int PRIMARY KEY, i1 int, v1 varchar(1), v2 varchar(1), KEY v1 (v1,i1)
+) engine=MyISAM;
+INSERT INTO t1 VALUES
+(8,3,'c','c'),(9,4,'z','z'),(10,3,'i','i'),(11,186,'x','x'),
+(14,226,'m','m'),(15,133,'p','p');
+CREATE TABLE t2 (
+pk int PRIMARY KEY, i1 int, v1 varchar(1), v2 varchar(1)
+) engine=MyISAM;
+INSERT INTO t2 VALUES (10,6,'p','p');
+EXPLAIN EXTENDED
+SELECT STRAIGHT_JOIN t2.v2
+FROM
+(t1 as tb1 LEFT JOIN t1 AS tb2 ON tb2.v1 = tb1.v2)
+RIGHT JOIN
+(t2,t1)
+ON t1.pk = t2.pk AND t2.v2 = tb1.v1
+WHERE tb1.pk = 40
+ORDER BY tb1.i1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+Warnings:
+Note	1003	select straight_join 'p' AS `v2` from `test`.`t1` join `test`.`t1` `tb1` left join `test`.`t1` `tb2` on(multiple equal(NULL, NULL)) where 0 order by NULL
+EXPLAIN EXTENDED
+SELECT STRAIGHT_JOIN t2.v2
+FROM
+(t2,t1)
+LEFT JOIN
+(t1 as tb1 LEFT JOIN t1 AS tb2 ON tb2.v1 = tb1.v2)
+ON t1.pk = t2.pk AND t2.v2 = tb1.v1
+WHERE tb1.pk = 40
+ORDER BY tb1.i1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+Warnings:
+Note	1003	select straight_join 'p' AS `v2` from `test`.`t1` join `test`.`t1` `tb1` left join `test`.`t1` `tb2` on(multiple equal(NULL, NULL)) where 0 order by NULL
+SELECT STRAIGHT_JOIN DISTINCT t2.v2
+FROM
+(t1 as tb1 LEFT JOIN t1 AS tb2 ON tb2.v1 = tb1.v2)
+RIGHT JOIN
+(t2,t1)
+ON t1.pk = t2.pk AND t2.v2 = tb1.v1
+WHERE tb1.pk = 40
+ORDER BY tb1.i1;
+v2
+DROP TABLE t1,t2;
 # end of 5.5 tests
 SET optimizer_switch=@save_optimizer_switch;