Fixed bug mdev-11364.

The function Item_func_isnull::update_used_tables() must
handle the case when the predicate is over not nullable
column in a special way.
This is actually a bug of MariaDB 5.3/5.5, but it's probably
hard to demonstrate that it can cause problems there.

1 files changed, 21 insertions, 0 deletions

diff --git a/mysql-test/r/selectivity_innodb.result b/mysql-test/r/selectivity_innodb.result
index 3d15131dbb5..a026c2e6d92 100644
--- a/mysql-test/r/selectivity_innodb.result
+++ b/mysql-test/r/selectivity_innodb.result
@@ -1521,6 +1521,27 @@ Note	1003	select `test`.`t2`.`col1` AS `col1` from `test`.`t2` where 0
 drop table t1,t2;
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
 set use_stat_tables=@save_use_stat_tables;
+#
+# Bug mdev-11364: IS NULL over not nullable datetime column
+#                 in mergeable derived
+#
+set use_stat_tables='preferably';
+set optimizer_use_condition_selectivity=4;
+set HISTOGRAM_SIZE = 255;
+CREATE TABLE t1 (t TIME, d DATE NOT NULL);
+INSERT INTO t1 VALUES ('10:00:00', '0000-00-00'),('11:00:00','0000-00-00');
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SELECT * FROM (SELECT t FROM t1 WHERE d IS NULL) sq;
+t
+10:00:00
+11:00:00
+DROP TABLE t1;
+set histogram_size=@save_histogram_size;
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+set use_stat_tables=@save_use_stat_tables;
 set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
 set @tmp_ust= @@use_stat_tables;
 set @tmp_oucs= @@optimizer_use_condition_selectivity;