Fixed a bug in key optimizing handling where the expression

WHERE column_name = key_column_name was calculated as true
for NULL values.


Docs/manual.texi:
  Changelog
mysql-test/r/distinct.result:
  Updated results caused by bug fix.
mysql-test/r/null_key.result:
  New tests
mysql-test/t/null_key.test:
  New tests
sql/sql_select.cc:
  Additional change for previous changeset for using BLOB in GROUP BY

1 files changed, 44 insertions, 0 deletions

diff --git a/mysql-test/t/null_key.test b/mysql-test/t/null_key.test
index e5d8fc59e4f..3ab8b993f43 100644
--- a/mysql-test/t/null_key.test
+++ b/mysql-test/t/null_key.test
@@ -91,3 +91,47 @@ DELETE FROM t2 WHERE uniq_id IS NULL;
 SELECT * FROM t1 ORDER BY uniq_id, id;
 SELECT * FROM t2 ORDER BY uniq_id, id;
 DROP table t1,t2;
+
+#
+# This crashed MySQL 3.23.47
+#
+
+CREATE TABLE `t1` (
+  `order_id` char(32) NOT NULL default '',
+  `product_id` char(32) NOT NULL default '',
+  `product_type` int(11) NOT NULL default '0',
+  PRIMARY KEY  (`order_id`,`product_id`,`product_type`)
+) TYPE=MyISAM;
+CREATE TABLE `t2` (
+  `order_id` char(32) NOT NULL default '',
+  `product_id` char(32) NOT NULL default '',
+  `product_type` int(11) NOT NULL default '0',
+  PRIMARY KEY  (`order_id`,`product_id`,`product_type`)
+) TYPE=MyISAM;
+INSERT INTO t1 (order_id, product_id, product_type) VALUES
+('3d7ce39b5d4b3e3d22aaafe9b633de51',1206029, 3),
+('3d7ce39b5d4b3e3d22aaafe9b633de51',5880836, 3),
+('9d9aad7764b5b2c53004348ef8d34500',2315652, 3);
+INSERT INTO t2 (order_id, product_id, product_type) VALUES
+('9d9aad7764b5b2c53004348ef8d34500',2315652, 3);
+
+select t1.* from t1
+left join t2 using(order_id, product_id, product_type)
+where t2.order_id=NULL;
+select t1.* from t1
+left join t2 using(order_id, product_id, product_type)
+where t2.order_id is NULL;
+drop table t1,t2;
+
+#
+# The last select returned wrong results in 3.23.52
+#
+
+create table t1 (id int);
+insert into t1 values (null), (0);
+create table t2 (id int);
+insert into t2 values (null);
+select * from t1, t2 where t1.id = t2.id;
+alter table t1 add key id (id);
+select * from t1, t2 where t1.id = t2.id;
+drop table t1,t2;