mariadb/mysql-test/r/table_elim.result

drop table if exists t0, t1, t2, t3;
drop view if exists v1, v2;
create table t1 (a int);
insert into t1 values (0),(1),(2),(3);
create table t0 as select * from t1;
create table t2 (a int primary key, b int) 
as select a, a as b from t1 where a in (1,2);
create table t3 (a int primary key, b int) 
as select a, a as b from t1 where a in (1,3);
# This will be  eliminated:
explain select t1.a from t1 left join t2 on t2.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
explain extended select t1.a from t1 left join t2 on t2.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	100.00	
Warnings:
Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where 1
select t1.a from t1 left join t2 on t2.a=t1.a;
a
0
1
2
3
# This will not be eliminated as t2.b is in in select list:
explain select * from t1 left join t2 on t2.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	
# This will not be eliminated as t2.b is in in order list:
explain select t1.a from t1 left join t2 on t2.a=t1.a order by t2.b;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	
# This will not be eliminated as t2.b is in group list:
explain select t1.a from t1 left join t2 on t2.a=t1.a group by t2.b;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	
# This will not be eliminated as t2.b is in the WHERE
explain select t1.a from t1 left join t2 on t2.a=t1.a where t2.b < 3 or t2.b is null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	Using where
# Elimination of multiple tables:
explain select t1.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
# Elimination of multiple tables (2):
explain select t1.a from t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and t3.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
# Elimination when done within an outer join nest:
explain extended
select t0.*
from
t0 left join (t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and
t3.a=t1.a) on t0.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	4	100.00	
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	100.00	
Warnings:
Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t0` left join (`test`.`t1`) on((`test`.`t0`.`a` = `test`.`t1`.`a`)) where 1
# Elimination with aggregate functions
explain select count(*) from t1 left join t2 on t2.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
explain select count(1) from t1 left join t2 on t2.a=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
explain select count(1) from t1 left join t2 on t2.a=t1.a group by t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
This must not use elimination:
explain select count(1) from t1 left join t2 on t2.a=t1.a group by t2.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	Using index
drop table t0, t1, t2, t3;
create table t0 ( id integer, primary key (id));
create table t1 (
id integer,
attr1 integer,
primary key (id),
key (attr1)
);
create table t2 (
id integer,
attr2 integer,
fromdate date,
primary key (id, fromdate),
key (attr2,fromdate)
);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
insert into t0 select A.id + 10*B.id from t0 A, t0 B where B.id > 0;
insert into t1 select id, id from t0;
insert into t2 select id, id, date_add('2009-06-22', interval id day) from t0;
insert into t2 select id, id+1, date_add('2008-06-22', interval id day) from t0;
create view v1 as
select 
F.id, A1.attr1, A2.attr2
from 
t0 F 
left join t1 A1 on A1.id=F.id
left join t2 A2 on A2.id=F.id and 
A2.fromdate=(select MAX(fromdate) from
t2 where id=A2.id);
create view v2 as
select 
F.id, A1.attr1, A2.attr2
from 
t0 F 
left join t1 A1 on A1.id=F.id
left join t2 A2 on A2.id=F.id and 
A2.fromdate=(select MAX(fromdate) from
t2 where id=F.id);
This should use one table:
explain select id from v1 where id=2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	F	const	PRIMARY	PRIMARY	4	const	1	Using index
This should use one table:
explain extended select id from v1 where id in (1,2,3,4);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	F	range	PRIMARY	PRIMARY	4	NULL	4	100.00	Using where; Using index
Warnings:
Note	1276	Field or reference 'test.A2.id' of SELECT #3 was resolved in SELECT #1
Note	1003	select `F`.`id` AS `id` from `test`.`t0` `F` where (`F`.`id` in (1,2,3,4))
This should use facts and A1 tables:
explain extended select id from v1 where attr1 between 12 and 14;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	A1	range	PRIMARY,attr1	attr1	5	NULL	2	100.00	Using where
1	PRIMARY	F	eq_ref	PRIMARY	PRIMARY	4	test.A1.id	1	100.00	Using index
Warnings:
Note	1276	Field or reference 'test.A2.id' of SELECT #3 was resolved in SELECT #1
Note	1003	select `F`.`id` AS `id` from `test`.`t0` `F` join `test`.`t1` `A1` where ((`F`.`id` = `A1`.`id`) and (`A1`.`attr1` between 12 and 14))
This should use facts, A2 and its subquery:
explain extended select id from v1 where attr2 between 12 and 14;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	A2	range	PRIMARY,attr2	attr2	5	NULL	5	100.00	Using where
1	PRIMARY	F	eq_ref	PRIMARY	PRIMARY	4	test.A2.id	1	100.00	Using index
3	DEPENDENT SUBQUERY	t2	ref	PRIMARY	PRIMARY	4	test.A2.id	2	100.00	Using index
Warnings:
Note	1276	Field or reference 'test.A2.id' of SELECT #3 was resolved in SELECT #1
Note	1003	select `F`.`id` AS `id` from `test`.`t0` `F` join `test`.`t2` `A2` where ((`F`.`id` = `A2`.`id`) and (`A2`.`attr2` between 12 and 14) and (`A2`.`fromdate` = (select max(`test`.`t2`.`fromdate`) AS `MAX(fromdate)` from `test`.`t2` where (`test`.`t2`.`id` = `A2`.`id`))))
This should use one table:
explain select id from v2 where id=2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	F	const	PRIMARY	PRIMARY	4	const	1	Using index
This should use one table:
explain extended select id from v2 where id in (1,2,3,4);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	F	range	PRIMARY	PRIMARY	4	NULL	4	100.00	Using where; Using index
Warnings:
Note	1276	Field or reference 'test.F.id' of SELECT #3 was resolved in SELECT #1
Note	1003	select `F`.`id` AS `id` from `test`.`t0` `F` where (`F`.`id` in (1,2,3,4))
This should use facts and A1 tables:
explain extended select id from v2 where attr1 between 12 and 14;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	A1	range	PRIMARY,attr1	attr1	5	NULL	2	100.00	Using where
1	PRIMARY	F	eq_ref	PRIMARY	PRIMARY	4	test.A1.id	1	100.00	Using index
Warnings:
Note	1276	Field or reference 'test.F.id' of SELECT #3 was resolved in SELECT #1
Note	1003	select `F`.`id` AS `id` from `test`.`t0` `F` join `test`.`t1` `A1` where ((`F`.`id` = `A1`.`id`) and (`A1`.`attr1` between 12 and 14))
This should use facts, A2 and its subquery:
explain extended select id from v2 where attr2 between 12 and 14;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	A2	range	PRIMARY,attr2	attr2	5	NULL	5	100.00	Using where
1	PRIMARY	F	eq_ref	PRIMARY	PRIMARY	4	test.A2.id	1	100.00	Using where; Using index
3	DEPENDENT SUBQUERY	t2	ref	PRIMARY	PRIMARY	4	test.F.id	2	100.00	Using index
Warnings:
Note	1276	Field or reference 'test.F.id' of SELECT #3 was resolved in SELECT #1
Note	1003	select `F`.`id` AS `id` from `test`.`t0` `F` join `test`.`t2` `A2` where ((`F`.`id` = `A2`.`id`) and (`A2`.`attr2` between 12 and 14) and (`A2`.`fromdate` = (select max(`test`.`t2`.`fromdate`) AS `MAX(fromdate)` from `test`.`t2` where (`test`.`t2`.`id` = `F`.`id`))))
drop view v1, v2;
drop table t0, t1, t2;