SET optimizer_switch = 'derived_merge=on';

CREATE TABLE t1 (a INT) ENGINE=MyISAM;

INSERT INTO t1 VALUES (1),(2);

CREATE TABLE t2 (b INT) ENGINE=MyISAM;

INSERT INTO t2 VALUES (3),(4);

CREATE TABLE t3 (c INT) ENGINE=MyISAM;

INSERT INTO t3 VALUES (5),(6);

SELECT * FROM ( SELECT c FROM ( t1 INNER JOIN t2 ) RIGHT JOIN t3 ON a = c ) AS alias;

c

------

NULL

NULL

c

------

5

6

revno: 3574

committer: sanja@montyprogram.com

branch nick: work-maria-5.3-MDEV-486

timestamp: Wed 2012-09-05 23:23:58 +0300

message:

  MDEV-486 LP BUG#1010116 fix.

  Link view/derived table fields to a real table to check turning the table record to null row.

  Item_direct_view_ref wrapper now checks if table is turned to null row.

index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using join buffer (flat, BNL join)

1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (incremental, BNL join)

Warnings:

Note	1003	select `test`.`t3`.`c` AS `c` from `test`.`t3` left join (`test`.`t1` join `test`.`t2`) on((`test`.`t1`.`a` = `test`.`t3`.`c`)) where 1

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where

1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	

Warnings:

Note	1003	select `test`.`t3`.`c` AS `c` from `test`.`t3` left join (`test`.`t1` join `test`.`t2`) on((`test`.`t1`.`a` = `test`.`t3`.`c`)) where 1