DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (f FLOAT <CUSTOM_COL_OPTIONS>,
r REAL(20,3) <CUSTOM_COL_OPTIONS>,
d DOUBLE <CUSTOM_COL_OPTIONS>,
dp DOUBLE PRECISION (64,10) <CUSTOM_COL_OPTIONS>,
<CUSTOM_INDEX> f (f)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
t1	1	#	1	f	#	#	NULL	NULL	#	#		
INSERT INTO t1 (f,r,d,dp) VALUES
(1.2345,1422.22,1.2345,1234567.89),
(0,0,0,0),
(-1,-1,-1,-1),
(17.5843,4953453454.44,29229114.0,1111111.23),
(4644,1422.22,466664.999,0.5);
SELECT f FROM t1 ORDER BY f;
f
-1
0
1.2345
17.5843
4644
DROP TABLE t1;
CREATE TABLE t1 (f FLOAT <CUSTOM_COL_OPTIONS> PRIMARY KEY,
r REAL(20,3) <CUSTOM_COL_OPTIONS>,
d DOUBLE <CUSTOM_COL_OPTIONS>,
dp DOUBLE PRECISION (64,10) <CUSTOM_COL_OPTIONS>
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
t1	0	PRIMARY	1	f	#	#	NULL	NULL	#	#		
INSERT INTO t1 (f,r,d,dp) VALUES
(1.2345,1422.22,1.2345,1234567.89),
(0,0,0,0),
(-1,-1,-1,-1),
(17.5843,4953453454.44,29229114.0,1111111.23),
(4644,1422.22,466664.999,0.5);
EXPLAIN SELECT f FROM t1 ORDER BY f;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
#	#	#	#	#	PRIMARY	#	#	#	#
SELECT f FROM t1 ORDER BY f;
f
-1
0
1.2345
17.5843
4644
EXPLAIN SELECT f FROM t1 IGNORE INDEX (PRIMARY) ORDER BY f;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
#	#	#	#	#	NULL	#	#	#	#
SELECT f FROM t1 IGNORE INDEX (PRIMARY) ORDER BY f;
f
-1
0
1.2345
17.5843
4644
ALTER TABLE t1 DROP PRIMARY KEY;
ALTER TABLE t1 ADD UNIQUE KEY(d);
EXPLAIN SELECT d FROM t1 WHERE r > 0 and d > 0 ORDER BY d;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
#	#	#	#	#	d	#	#	#	#
SELECT d FROM t1 WHERE r > 0 and d > 0 ORDER BY d;
d
1.2345
466664.999
29229114
DROP TABLE t1;
CREATE TABLE t1 (f FLOAT <CUSTOM_COL_OPTIONS>,
r REAL(20,3) <CUSTOM_COL_OPTIONS>,
d DOUBLE <CUSTOM_COL_OPTIONS>,
dp DOUBLE PRECISION (64,10) <CUSTOM_COL_OPTIONS>,
UNIQUE KEY r_dp (r,dp)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
t1	0	r_dp	1	r	#	#	NULL	NULL	#	#		
t1	0	r_dp	2	dp	#	#	NULL	NULL	#	#		
INSERT INTO t1 (f,r,d,dp) VALUES
(1.2345,1422.22,1.2345,1234567.89),
(0,0,0,0),
(-1,-1,-1,-1),
(17.5843,4953453454.44,29229114.0,1111111.23),
(4644,1422.22,466664.999,0.5);
EXPLAIN SELECT r, dp FROM t1 WHERE r > 0 or dp > 0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
#	#	#	#	#	r_dp	#	#	#	#
SELECT r, dp FROM t1 WHERE r > 0 or dp > 0;
r	dp
1422.220	0.5000000000
1422.220	1234567.8900000000
4953453454.440	1111111.2300000000
DROP TABLE t1;
CREATE TABLE t1 (f FLOAT <CUSTOM_COL_OPTIONS>,
r REAL(20,3) <CUSTOM_COL_OPTIONS>,
d DOUBLE <CUSTOM_COL_OPTIONS>,
dp DOUBLE PRECISION (64,10) <CUSTOM_COL_OPTIONS>,
UNIQUE KEY(d)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
t1	0	d	1	d	#	#	NULL	NULL	#	#		
INSERT INTO t1 (f,r,d,dp) VALUES
(1.2345,1422.22,1.2345,1234567.89),
(0,0,0,0),
(-1,-1,-1,-1),
(17.5843,4953453454.44,29229114.0,1111111.23),
(4644,1422.22,466664.999,0.5);
EXPLAIN SELECT DISTINCT d FROM t1 ORDER BY d;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
#	#	#	#	#	d	#	#	#	#
SELECT DISTINCT d FROM t1 ORDER BY d;
d
-1
0
1.2345
466664.999
29229114
DROP TABLE t1;
CREATE TABLE t1 (f FLOAT <CUSTOM_COL_OPTIONS>,
r REAL(20,3) <CUSTOM_COL_OPTIONS>,
d DOUBLE <CUSTOM_COL_OPTIONS>,
dp DOUBLE PRECISION (64,10) <CUSTOM_COL_OPTIONS>,
KEY(d)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
t1	1	d	1	d	#	#	NULL	NULL	#	#		
INSERT INTO t1 (f,r,d,dp) VALUES
(1.2345,1422.22,1.2345,1234567.89),
(0,0,0,0),
(-1,-1,-1,-1),
(17.5843,4953453454.44,29229114.0,1111111.23),
(4644,1422.22,466664.999,0.5);
EXPLAIN SELECT DISTINCT d FROM t1 ORDER BY d;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
#	#	#	#	#	d	#	#	#	#
SELECT DISTINCT d FROM t1 ORDER BY d;
d
-1
0
1.2345
466664.999
29229114
DROP TABLE t1;