Commit ad57284c authored by unknown's avatar unknown
Browse files

join_nested.result, join_nested.test: 

  Added a teast case for bug #11284.
sql_select.cc:
  Fixed bug #11284.
  Optimization with empty inner table currently cannot be
  used in the case of nested outer join.


sql/sql_select.cc:
  Fixed bug #11284.
  Optimization with empty inner table currently cannot be
  used in the case of nested outer join.
mysql-test/t/join_nested.test:
  Added a teast case for bug #11284.
parent 67c204c4

mysql-test/r/join_nested.result

+22 −0
Original line number Diff line number Diff line
@@ -1321,3 +1321,25 @@ NULL NULL NULL 
18	NULL	NULL

19	NULL	NULL

DROP TABLE t1,t2,t3;

CREATE TABLE t1 (c11 int);

CREATE TABLE t2 (c21 int);

CREATE TABLE t3 (c31 int);

INSERT INTO t1 VALUES (4), (5);

SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;

c11	c21

4	NULL

5	NULL

EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	0	const row not found

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	

SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;

c11	c21	c31

4	NULL	NULL

5	NULL	NULL

EXPLAIN SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	

1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	

1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	

DROP TABLE t1,t2,t3;

mysql-test/t/join_nested.test

+18 −0
Original line number Diff line number Diff line
@@ -752,3 +752,21 @@ EXPLAIN SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c; 
SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;



DROP TABLE t1,t2,t3;



#

# Test for bug #11284: empty table in a nested left join

# 



CREATE TABLE t1 (c11 int);

CREATE TABLE t2 (c21 int);

CREATE TABLE t3 (c31 int);



INSERT INTO t1 VALUES (4), (5);



SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;

EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;



SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;

EXPLAIN SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;



DROP TABLE t1,t2,t3;

sql/sql_select.cc

+1 −1
Original line number Diff line number Diff line
@@ -2158,7 +2158,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds, 
    if (*s->on_expr_ref)

    {

      /* s is the only inner table of an outer join */

      if (!table->file->records)

      if (!table->file->records && !embedding)

      {						// Empty table

        s->dependent= 0;                        // Ignore LEFT JOIN depend.

	set_position(join,const_count++,s,(KEYUSE*) 0);