derived_opt.result 14.3 KB
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drop table if exists t1,t2,t3;
set @exit_optimizer_switch=@@optimizer_switch;
set optimizer_switch='derived_merge=on,derived_with_keys=on';
set @save_optimizer_switch=@@optimizer_switch;
CREATE TABLE t1 (a int not null, b char (10) not null);
insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
CREATE TABLE t2 (a int not null, b char (10) not null);
insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
CREATE TABLE t3 (a int not null, b char (10) not null);
insert into t3 values (3,'f'),(4,'y'),(5,'z'),(6,'c');
select * from t1 as x1, (select * from t1) as x2;
a	b	a	b
1	a	1	a
2	b	1	a
3	c	1	a
3	c	1	a
1	a	2	b
2	b	2	b
3	c	2	b
3	c	2	b
1	a	3	c
2	b	3	c
3	c	3	c
3	c	3	c
1	a	3	c
2	b	3	c
3	c	3	c
3	c	3	c
explain select * from t1 as x1, (select * from t1) as x2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	x1	ALL	NULL	NULL	NULL	NULL	4	
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
drop table if exists  t2,t3;
CREATE TABLE t2 (a int not null);
insert into t2 values(1);
select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
a	b	t2a
1	a	1
explain select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
drop table t1, t2;
create table t1(a int not null, t char(8), index(a));
SELECT * FROM (SELECT * FROM t1) as b ORDER BY a  ASC LIMIT 0,20;
a	t
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	8
9	9
10	10
11	11
12	12
13	13
14	14
15	15
16	16
17	17
18	18
19	19
20	20
explain select count(*) from t1 as tt1, (select * from t1) as tt2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
drop table t1;
create table t1 (mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, matintnum CHAR(6) NOT NULL, test MEDIUMINT UNSIGNED NULL);
create table t2 (mat_id MEDIUMINT UNSIGNED NOT NULL, pla_id MEDIUMINT UNSIGNED NOT NULL);
insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4), (NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8), (NULL, 'i', 9);
insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
pla_id	mat_id
102	1
101	1
100	1
104	2
103	2
105	3
SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
pla_id	test
102	1
101	1
100	1
104	2
103	2
105	3
explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
drop table t1,t2;
create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
);
insert into t1 VALUES(1,1,1), (2,2,1);
select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
count(*)
2
explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	2	Using where
1	PRIMARY	t1	eq_ref	PRIMARY	PRIMARY	4	test.A.E2	1	Using where
3	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	2	Using where
drop table t1;
create table t1 (a int);
insert into t1 values (1),(2);
select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
a	a
1	1
2	1
1	2
2	2
explain select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	
1	PRIMARY	<derived4>	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
4	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
5	UNION	t1	ALL	NULL	NULL	NULL	NULL	2	
NULL	UNION RESULT	<union4,5>	ALL	NULL	NULL	NULL	NULL	NULL	
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
3	UNION	t1	ALL	NULL	NULL	NULL	NULL	2	
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
drop table t1;
create table t2 (a int, b int, primary key (a));
insert into t2 values (1,7),(2,7);
explain select a from t2 where a>1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
explain select a from (select a from t2 where a>1) tt;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
drop table t2;
create table t1 
(
c1  tinyint, c2  smallint, c3  mediumint, c4  int,
c5  integer, c6  bigint, c7  float, c8  double,
c9  double precision, c10 real, c11 decimal(7, 4), c12 numeric(8, 4),
c13 date, c14 datetime, c15 timestamp, c16 time,
c17 year, c18 bit, c19 bool, c20 char,
c21 char(10), c22 varchar(30), c23 tinyblob, c24 tinytext,
c25 blob, c26 text, c27 mediumblob, c28 mediumtext,
c29 longblob, c30 longtext, c31 enum('one', 'two', 'three'),
c32 set('monday', 'tuesday', 'wednesday')
) engine = MYISAM ;
create table t2 like t1;
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch="partial_match_rowid_merge=off,partial_match_table_scan=off";
set @stmt= ' explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25 ' ;
prepare stmt1 from @stmt ;
execute stmt1 ;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
5	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
4	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
execute stmt1 ;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
5	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
4	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
5	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
4	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
deallocate prepare stmt1;
drop tables t1,t2;
set @@optimizer_switch=@save_optimizer_switch;
#
#  LP bug #793436: query with a derived table for which optimizer proves
#                  that it contains not more than 1 row
#
CREATE TABLE t1 (a int, KEY (a)) ;
INSERT INTO t1 VALUES (3), (1);
CREATE TABLE t2 (a int);
INSERT INTO t2 VALUES (3);
EXPLAIN
SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
1	PRIMARY	t1	ref	a	a	5	const	1	Using index
2	DERIVED	t2	system	NULL	NULL	NULL	NULL	1	
SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
a	a
3	3
DROP TABLE t1,t2;
#
#  LP bug #800518: crash with a query over a derived table
#                  when a min/max optimization is applied
#
CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
INSERT INTO t1 VALUES 
(100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
(200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
EXPLAIN
SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
MAX(b)
5
DROP TABLE t1;
#
#  LP bug #799499: query over a materialized view 
#                  accessed by a key
#
CREATE TABLE t1 (a int) ;
INSERT INTO t1 VALUES (8);
CREATE TABLE t2 (a int, b int) ;
INSERT INTO t2 VALUES
(262, NULL), (253, 190), (260, NULL), (250, 163), (188, 8),
(257,200), (256, NULL), (255, 8), (249, NULL), (259, 7);
CREATE VIEW v1 AS SELECT a, MIN(b) AS b FROM t2 GROUP BY a;
EXPLAIN
SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	Using filesort
1	PRIMARY	<derived2>	ref	key0	key0	5	const	1	Using where
2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	10	Using temporary; Using filesort
SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
a	b	a
188	8	8
255	8	8
DROP VIEW v1;
DROP TABLE t1,t2;
#
#  LP bug #800085: crash with a query using a simple derived table 
#                  (fixed by the patch for bug 798621)
#
CREATE TABLE t1 (f1 int, f2 varchar(32)) ;
INSERT INTO t1 VALUES (NULL,'j'), (8,'c');
CREATE TABLE t2 (f1 int);
INSERT INTO t2 VALUES (1), (5);
SELECT DISTINCT t.f1 FROM (SELECT * FROM t1) AS t, t2
WHERE t.f2='s' AND t.f2 LIKE '%a%' OR t.f1<>0 ORDER BY t.f2;
f1
8
DROP TABLE t1, t2;
#
# BUG##806524: Assertion `join->best_read < 1.7976931348623157e+308 with table_elimination=on and derived_merge=on 
# 
CREATE TABLE t1 ( f4 int) ;
CREATE TABLE t2 ( f4 int) ;
CREATE TABLE t3 ( f1 int NOT NULL , PRIMARY KEY (f1)) ;
CREATE TABLE t4 ( f2 int, f4 int) ;
SELECT *
FROM ( SELECT * FROM t1 ) AS alias1
RIGHT JOIN (
t2 AS alias2
LEFT JOIN (
SELECT t4.*
FROM ( SELECT * FROM t3 ) AS SQ1_alias1
RIGHT JOIN t4
ON t4.f2 = SQ1_alias1.f1
) AS alias3
ON alias3.f4 != 0
) ON alias3.f4 != 0;
f4	f4	f2	f4
drop table t1,t2,t3,t4;
#
# LP BUG#910123 MariaDB 5.3.3 causes 1093 error on Drupal
# Fix: force materialization in case of conflict
#
SET optimizer_switch='derived_merge=on';
CREATE TABLE t1 ( i INT );
INSERT INTO t1 VALUES ( (SELECT 1 FROM ( SELECT * FROM t1 ) as a) );
drop table t1;
set optimizer_switch=@save_optimizer_switch;
#
# MDEV-3801 Reproducible sub select join crash on 5.3.8 and 5.3.9 
#
CREATE TABLE t1 (
pk int(10) unsigned NOT NULL AUTO_INCREMENT,
a char(2) DEFAULT NULL,
PRIMARY KEY (pk),
KEY a (a)
) ENGINE=MyISAM;
INSERT INTO t1 (a)
VALUES (NULL),(NULL),(NULL),('AB'),(NULL),('CD'),(NULL),(NULL);
INSERT INTO t1 SELECT NULL, a1.a FROM t1 a1, t1 a2, t1 a3, t1 a4, t1 a5;
CREATE TABLE t2 (
pk int(10) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY
) ENGINE=MyISAM;
INSERT INTO t2 VALUES (NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL);
INSERT INTO t2 SELECT NULL FROM t2 a1, t2 a2, t2 a3, t2 a4, t2 a5;
CREATE TABLE t3 (
pk int(10) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY
) ENGINE=MyISAM;
INSERT INTO t3 VALUES (NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL);
INSERT INTO t3 SELECT NULL FROM t3 a1, t3 a2, t3 a3, t3 a4, t3 a5;
CREATE TABLE t4 (
a char(2) NOT NULL DEFAULT '',
PRIMARY KEY (a)
) ENGINE=MyISAM;
INSERT INTO t4 VALUES ('CD');
set @@tmp_table_size=8192;
EXPLAIN
SELECT * FROM t3 AS tx JOIN t2 AS ty ON (tx.pk = ty.pk)
WHERE
tx.pk IN
(SELECT *
FROM (SELECT DISTINCT ta.pk
FROM t3 AS ta
JOIN t2 AS tb ON (ta.pk = tb.pk)
JOIN t1 AS tc ON (tb.pk = tc.pk)
JOIN t4 AS td ON tc.a = td.a) tu)
limit 10;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	#	
1	PRIMARY	tx	eq_ref	PRIMARY	PRIMARY	4	tu.pk	#	Using index
1	PRIMARY	ty	eq_ref	PRIMARY	PRIMARY	4	tu.pk	#	Using index
2	MATERIALIZED	<derived3>	ALL	NULL	NULL	NULL	NULL	#	
3	DERIVED	td	system	PRIMARY	NULL	NULL	NULL	#	Using temporary
3	DERIVED	tc	ref	PRIMARY,a	a	3	const	#	
3	DERIVED	ta	eq_ref	PRIMARY	PRIMARY	4	test.tc.pk	#	Using index
3	DERIVED	tb	eq_ref	PRIMARY	PRIMARY	4	test.tc.pk	#	Using index; Distinct
SELECT * FROM t3 AS tX JOIN t2 AS tY ON (tX.pk = tY.pk)
WHERE
tX.pk IN
(SELECT *
FROM (SELECT DISTINCT tA.pk
FROM t3 AS tA
JOIN t2 AS tB ON (tA.pk = tB.pk)
JOIN t1 AS tC ON (tB.pk = tC.pk)
JOIN t4 AS tD ON tC.a = tD.a) tU)
limit 10;
pk	pk
6	6
16	16
24	24
32	32
40	40
48	48
56	56
64	64
72	72
80	80
drop table t1, t2, t3, t4;
set optimizer_switch=@exit_optimizer_switch;