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# MDEV-27576 Use DESC indexes for MIN/MAX optimization
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create or replace table t1 (a int, key(a desc)) engine=innodb;
insert into t1 select seq * 2 from seq_1_to_100 order by rand(1);
explain select max(a) from t1;
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(a) from t1;
max(a)
200
explain select min(a) from t1;
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 min(a) from t1;
min(a)
2
explain select max(a) from t1 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(a) from t1 where a < 100;
max(a)
98
explain select min(a) from t1 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 min(a) from t1 where a > 100;
min(a)
102
explain select max(a) from t1 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(a) from t1 where a <= 100;
max(a)
100
explain select min(a) from t1 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 min(a) from t1 where a >= 100;
min(a)
100
explain select max(a) from t1 where a <= 99;
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(a) from t1 where a <= 99;
max(a)
98
explain select min(a) from t1 where a >= 99;
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 min(a) from t1 where a >= 99;
min(a)
100
explain select max(a) from t1 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(a) from t1 where a > 100;
max(a)
200
explain select max(a) from t1 where a > 1000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
select max(a) from t1 where a > 1000;
max(a)
NULL
explain select min(a) from t1 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 min(a) from t1 where a < 100;
min(a)
2
explain select min(a) from t1 where a < 0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
select min(a) from t1 where a < 0;
min(a)
NULL
explain select max(a) from t1 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(a) from t1 where a >= 100;
max(a)
200
explain select max(a) from t1 where a >= 1000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
select max(a) from t1 where a >= 1000;
max(a)
NULL
explain select min(a) from t1 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 min(a) from t1 where a <= 100;
min(a)
2
explain select min(a) from t1 where a <= 0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
select min(a) from t1 where a <= 0;
min(a)
NULL
explain select max(a) from t1 where a >= 99;
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(a) from t1 where a >= 99;
max(a)
200
explain select min(a) from t1 where a <= 99;
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 min(a) from t1 where a <= 99;
min(a)
2
explain select max(200 - a) from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	5	NULL	100	Using index
select max(200 - a) from t1;
max(200 - a)
198
explain select min(200 - a) from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	5	NULL	100	Using index
select min(200 - a) from t1;
min(200 - a)
0
create or replace table t1 (a int, b int, key(a desc, b asc)) engine=innodb;
insert into t1 select seq * 2, seq * 2 from seq_1_to_100 order by rand(1);
explain select max(a) from t1;
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(a) from t1;
max(a)
200
explain select min(a) from t1;
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 min(a) from t1;
min(a)
2
create or replace table t1 (a int, b int, key(a asc), key (b desc)) engine=innodb;
insert into t1 select seq * 2, seq * 2 from seq_1_to_100 order by rand(1);
explain select max(b) from t1;
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 t1;
max(b)
200
explain select min(b) from t1;
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 min(b) from t1;
min(b)
2
create or replace table t1 (a int, b int, key (b desc)) engine=innodb;
insert into t1 select seq * 2, seq * 2 from seq_1_to_100 order by rand(1);
explain select max(b) from t1;
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 t1;
max(b)
200
explain select min(b) from t1;
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 min(b) from t1;
min(b)
2
CREATE OR REPLACE TABLE t1 (a FLOAT, KEY (a DESC));
INSERT INTO t1 VALUES (0.1234),(0.6789);
explain SELECT MAX(a) FROM t1 WHERE a <= 0.6789;
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(a) FROM t1 WHERE a <= 0.6789;
MAX(a)
0.6789
drop table t1;
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# end of test 11.4
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