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Fixed bug #16260.

Browse source 
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.
This commit is contained in:
unknown 2006-01-27 21:20:28 -08:00
parent ae951e0f72
commit 6bfbba34c7
3 changed files with 53 additions and 1 deletions
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23
mysql-test/r/join_nested.result
View file

@ -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;

28
mysql-test/t/join_nested.test
View file

@ -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;

3
sql/sql_select.cc
View file

@ -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.