Commit 6bfbba34 authored by unknown's avatar unknown
Browse files

Fixed bug #16260. 

The problem has manifested itself in the cases when we have a nested outer join
for which it can be inferred that one of the inner tables is a single row table.


mysql-test/r/join_nested.result:
  Added a test case for bug #16260.
mysql-test/t/join_nested.test:
  Added a test case for bug #16260.
sql/sql_select.cc:
  Fixed bug #16260.
  The problem has manifested itself in the cases when we have a nested outer join
  for which it can be inferred that one of the inner tables is a single row table.
  A table is never considered as a const table if it is used in a nested join 
  that serves as an inner operand of an outer join.
parent ae951e0f

mysql-test/r/join_nested.result

+23 −0
Original line number Diff line number Diff line
@@ -1481,3 +1481,26 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	SIMPLE	t2	ref	a	a	5	test.t1.a	1	

1	SIMPLE	t3	ref	a	a	5	test.t2.a	1	

drop table t1, t2, t3;

CREATE TABLE t1 (id int NOT NULL PRIMARY KEY, type varchar(10));

CREATE TABLE t2 (pid int NOT NULL PRIMARY KEY, type varchar(10));

CREATE TABLE t3 (cid int NOT NULL PRIMARY KEY,

id int NOT NULL,

pid int NOT NULL);

INSERT INTO t1 VALUES (1, 'A'), (3, 'C');

INSERT INTO t2 VALUES (1, 'A'), (3, 'C');

INSERT INTO t3 VALUES (1, 1, 1), (3, 3, 3);

SELECT * FROM t1 p LEFT JOIN (t3 JOIN t1)

ON (t1.id=t3.id AND t1.type='B' AND p.id=t3.id)

LEFT JOIN t2 ON (t3.pid=t2.pid)

WHERE p.id=1;

id	type	cid	id	pid	id	type	pid	type

1	A	NULL	NULL	NULL	NULL	NULL	NULL	NULL

CREATE VIEW v1 AS

SELECT t3.* FROM t3 JOIN t1 ON t1.id=t3.id AND t1.type='B';

SELECT * FROM t1 p LEFT JOIN v1 ON p.id=v1.id

LEFT JOIN t2 ON v1.pid=t2.pid

WHERE p.id=1;

id	type	cid	id	pid	pid	type

1	A	NULL	NULL	NULL	NULL	NULL

DROP VIEW v1;

DROP TABLE t1,t2,t3;

mysql-test/t/join_nested.test

+28 −0
Original line number Diff line number Diff line
@@ -914,3 +914,31 @@ explain select * from t1 left join 
  on (t1.a = t2.a);

drop table t1, t2, t3;



#

# Bug #16260: single row table in the inner nest of an outer join  

#



CREATE TABLE t1 (id int NOT NULL PRIMARY KEY, type varchar(10));

CREATE TABLE t2 (pid int NOT NULL PRIMARY KEY, type varchar(10));

CREATE TABLE t3 (cid int NOT NULL PRIMARY KEY,

                 id int NOT NULL,

                 pid int NOT NULL);



INSERT INTO t1 VALUES (1, 'A'), (3, 'C');

INSERT INTO t2 VALUES (1, 'A'), (3, 'C');

INSERT INTO t3 VALUES (1, 1, 1), (3, 3, 3);



SELECT * FROM t1 p LEFT JOIN (t3 JOIN t1)

                     ON (t1.id=t3.id AND t1.type='B' AND p.id=t3.id)

                   LEFT JOIN t2 ON (t3.pid=t2.pid)

  WHERE p.id=1;



CREATE VIEW v1 AS

  SELECT t3.* FROM t3 JOIN t1 ON t1.id=t3.id AND t1.type='B';



SELECT * FROM t1 p LEFT JOIN v1 ON p.id=v1.id

                   LEFT JOIN t2 ON v1.pid=t2.pid

  WHERE p.id=1;



DROP VIEW v1;

DROP TABLE t1,t2,t3;

sql/sql_select.cc

+2 −1
Original line number Diff line number Diff line
@@ -2172,7 +2172,8 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds, 
	  if (eq_part.is_prefix(table->key_info[key].key_parts) &&

	      ((table->key_info[key].flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==

	       HA_NOSAME) &&

              !table->fulltext_searched)

              !table->fulltext_searched && 

              !table->pos_in_table_list->embedding)

	  {

	    if (const_ref == eq_part)

	    {					// Found everything for ref.