set @mrr_icp_extra_tmp=@@optimizer_switch;
set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
SET NAMES latin1;
CREATE TABLE t1 
(s1 char(10) COLLATE latin1_german1_ci,
s2 char(10) COLLATE latin1_swedish_ci,
KEY(s1),
KEY(s2));
INSERT INTO t1 VALUES ('a','a');
INSERT INTO t1 VALUES ('b','b');
INSERT INTO t1 VALUES ('c','c');
INSERT INTO t1 VALUES ('d','d');
INSERT INTO t1 VALUES ('e','e');
INSERT INTO t1 VALUES ('f','f');
INSERT INTO t1 VALUES ('g','g');
INSERT INTO t1 VALUES ('h','h');
INSERT INTO t1 VALUES ('i','i');
INSERT INTO t1 VALUES ('j','j');
EXPLAIN SELECT * FROM t1 WHERE s1='a';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	s1	s1	11	const	1	Using index condition
EXPLAIN SELECT * FROM t1 WHERE s2='a';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	s2	s2	11	const	1	Using index condition
EXPLAIN SELECT * FROM t1 WHERE s1='a' COLLATE latin1_german1_ci;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	s1	s1	11	const	1	Using index condition
EXPLAIN SELECT * FROM t1 WHERE s2='a' COLLATE latin1_german1_ci;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
EXPLAIN SELECT * FROM t1 WHERE s1 BETWEEN 'a' AND 'b' COLLATE latin1_german1_ci;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	s1	s1	11	NULL	2	Using index condition; Rowid-ordered scan
EXPLAIN SELECT * FROM t1 WHERE s2 BETWEEN 'a' AND 'b' COLLATE latin1_german1_ci;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
EXPLAIN SELECT * FROM t1 WHERE s1 IN  ('a','b' COLLATE latin1_german1_ci);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	s1	s1	11	NULL	2	Using index condition; Rowid-ordered scan
EXPLAIN SELECT * FROM t1 WHERE s2 IN  ('a','b' COLLATE latin1_german1_ci);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
EXPLAIN SELECT * FROM t1 WHERE s1 LIKE 'a' COLLATE latin1_german1_ci;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	s1	s1	11	NULL	1	Using index condition; Rowid-ordered scan
EXPLAIN SELECT * FROM t1 WHERE s2 LIKE 'a' COLLATE latin1_german1_ci;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
DROP TABLE t1;
#
#
CREATE TABLE t2 (a varchar(32), b int(11), c float, d double, 
UNIQUE KEY a (a,b,c), KEY b (b), KEY c (c));
CREATE TABLE t1 (a varchar(32), b char(3), UNIQUE KEY a (a,b), KEY b (b));
CREATE TABLE t3 (a varchar(32), b char(3), UNIQUE KEY a (a,b));
INSERT INTO t3 SELECT * FROM t1;
EXPLAIN
SELECT d FROM t1, t2
WHERE t2.b=14 AND t2.a=t1.a AND 5.1<t2.c AND t1.b='DE'
ORDER BY t2.c LIMIT 1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
SELECT d FROM t1, t2
WHERE t2.b=14 AND t2.a=t1.a AND 5.1<t2.c AND t1.b='DE'
ORDER BY t2.c LIMIT 1;
d
DROP TABLE t1,t2,t3;
#
#
create table t1(a int, b int, index(b));
insert into t1 values (2, 1), (1, 1), (4, NULL), (3, NULL), (6, 2), (5, 2);
insert into t1 values (2, 11), (1, 11), (4, 14), (3, 14), (6, 12), (5, 12);
explain select * from t1 where b=1 or b is null order by a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref_or_null	b	b	5	const	4	Using index condition; Using where; Using filesort
select * from t1 where b=1 or b is null order by a;
a	b
1	1
2	1
3	NULL
4	NULL
explain select * from t1 where b=2 or b is null order by a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref_or_null	b	b	5	const	3	Using index condition; Using where; Using filesort
select * from t1 where b=2 or b is null order by a;
a	b
3	NULL
4	NULL
5	2
6	2
drop table t1;
#
#
CREATE TABLE t1 (
FieldKey varchar(36) NOT NULL default '',
LongVal bigint(20) default NULL,
StringVal mediumtext,
KEY FieldKey (FieldKey),
KEY LongField (FieldKey,LongVal),
KEY StringField (FieldKey,StringVal(32))
);
INSERT INTO t1 VALUES ('0',3,'0'),('0',2,'1'),('0',1,'2'),('1',2,'1'),('1',1,'3'), ('1',0,'2'),('2',3,'0'),('2',2,'1'),('2',1,'2'),('2',3,'0'),('2',2,'1'),('2',1,'2'),('3',2,'1'),('3',1,'2'),('3','3','3');
EXPLAIN SELECT * FROM t1 IGNORE INDEX (LongField, StringField) WHERE FieldKey > '2' ORDER BY LongVal;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	FieldKey	FieldKey	38	NULL	4	Using index condition; Rowid-ordered scan; Using filesort
EXPLAIN SELECT * FROM t1 IGNORE INDEX (FieldKey, LongField) WHERE FieldKey > '2' ORDER BY LongVal;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	StringField	StringField	38	NULL	4	Using index condition; Using filesort
SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY LongVal;
FieldKey	LongVal	StringVal
3	1	2
3	2	1
3	3	3
DROP TABLE t1;
#
#
CREATE TABLE t1 (a int not null, b int, c int, key(b), key(c), key(a,b), key(c,a));
INSERT into t1 values (0, null, 0), (0, null, 1), (0, null, 2), (0, null,3), (1,1,4);
create table t2 (a int not null, b int, c int, key(b), key(c), key(a));
INSERT into t2 values (1,1,1), (2,2,2);
optimize table t1;
Table	Op	Msg_type	Msg_text
test.t1	optimize	status	OK
explain select * from t1 force index (a) where a=0 or a=2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	4	NULL	4	Using index condition; Using where; Rowid-ordered scan
select * from t1 force index (a) where a=0 or a=2;
a	b	c
0	NULL	0
0	NULL	1
0	NULL	2
0	NULL	3
drop table t1;
#
#
create table t1
(
pk1 int not null,
pk2 int not null,
key1 int not null,
key2 int not null,
pktail1ok  int not null,
pktail2ok  int not null,
pktail3bad int not null,
pktail4bad int not null,
pktail5bad int not null,
pk2copy int not null,
badkey  int not null,
filler1 char (200),
filler2 char (200),
key (key1),
key (key2),
/* keys with tails from CPK members */
key (pktail1ok, pk1),
key (pktail2ok, pk1, pk2),
key (pktail3bad, pk2, pk1),
key (pktail4bad, pk1, pk2copy),
key (pktail5bad, pk1, pk2, pk2copy),
primary key (pk1, pk2)
);
explain select * from t1 where pk1 = 1 and pk2 < 80  and key1=0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	PRIMARY,key1	PRIMARY	8	NULL	7	Using index condition; Using where; Rowid-ordered scan
select * from t1 where pk1 = 1 and pk2 < 80  and key1=0;
pk1	pk2	key1	key2	pktail1ok	pktail2ok	pktail3bad	pktail4bad	pktail5bad	pk2copy	badkey	filler1	filler2
1	19	0	0	0	0	0	0	0	19	0	filler-data-19	filler2
1	18	0	0	0	0	0	0	0	18	0	filler-data-18	filler2
1	17	0	0	0	0	0	0	0	17	0	filler-data-17	filler2
1	16	0	0	0	0	0	0	0	16	0	filler-data-16	filler2
1	15	0	0	0	0	0	0	0	15	0	filler-data-15	filler2
1	14	0	0	0	0	0	0	0	14	0	filler-data-14	filler2
1	13	0	0	0	0	0	0	0	13	0	filler-data-13	filler2
1	12	0	0	0	0	0	0	0	12	0	filler-data-12	filler2
1	11	0	0	0	0	0	0	0	11	0	filler-data-11	filler2
1	10	0	0	0	0	0	0	0	10	0	filler-data-10	filler2
drop table t1;
#
#
CREATE TABLE t1 (
f1 int,
f4 varchar(32),
f5 int,
PRIMARY KEY (f1),
KEY (f4)
);
INSERT INTO t1 VALUES 
(5,'H',1), (9,'g',0), (527,'i',0), (528,'y',1), (529,'S',6),
(530,'m',7), (531,'b',2), (532,'N',1), (533,'V',NULL), (534,'l',1),
(535,'M',0), (536,'w',1), (537,'j',5), (538,'l',0), (539,'n',2),
(540,'m',2), (541,'r',2), (542,'l',2), (543,'h',3),(544,'o',0),
(956,'h',0), (957,'g',0), (958,'W',5), (959,'s',3), (960,'w',0),
(961,'q',0), (962,'e',NULL), (963,'u',7), (964,'q',1), (965,'N',NULL),
(966,'e',0), (967,'t',3), (968,'e',6), (969,'f',NULL), (970,'j',0),
(971,'s',3), (972,'I',0), (973,'h',4), (974,'g',1), (975,'s',0),
(976,'r',3), (977,'x',1), (978,'v',8), (979,'j',NULL), (980,'z',7),
(981,'t',9), (982,'j',5), (983,'u',NULL), (984,'g',6), (985,'w',1),
(986,'h',1), (987,'v',0), (988,'v',0), (989,'c',2), (990,'b',7),
(991,'z',0), (992,'M',1), (993,'u',2), (994,'r',2), (995,'b',4),
(996,'A',2), (997,'u',0), (998,'a',0), (999,'j',2), (1,'I',2);
EXPLAIN
SELECT * FROM t1
WHERE (f1 < 535  OR  f1 > 985) AND ( f4='r' OR f4 LIKE 'a%' ) ;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	PRIMARY,f4	f4	35	NULL	5	Using index condition; Using where; Rowid-ordered scan
SELECT * FROM t1
WHERE (f1 < 535  OR  f1 > 985) AND ( f4='r' OR f4 LIKE 'a%' ) ;
f1	f4	f5
994	r	2
996	A	2
998	a	0
drop table t1;
#
#
drop table if exists t1,t2,t3;
--- Testing varchar ---
--- Testing varchar ---
create table t1 (v varchar(10), c char(10), t text);
insert into t1 values('+ ', '+ ', '+ ');
set @a=repeat(' ',20);
insert into t1 values (concat('+',@a),concat('+',@a),concat('+',@a));
Warnings:
Note	1265	Data truncated for column 'v' at row 1
select concat('*',v,'*',c,'*',t,'*') from t1;
concat('*',v,'*',c,'*',t,'*')
*+ *+*+ *
*+         *+*+                    *
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(10) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text
) ENGINE=MyISAM DEFAULT CHARSET=latin1
create table t2 like t1;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `v` varchar(10) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text
) ENGINE=MyISAM DEFAULT CHARSET=latin1
create table t3 select * from t1;
show create table t3;
Table	Create Table
t3	CREATE TABLE `t3` (
  `v` varchar(10) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text
) ENGINE=MyISAM DEFAULT CHARSET=latin1
alter table t1 modify c varchar(10);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(10) DEFAULT NULL,
  `c` varchar(10) DEFAULT NULL,
  `t` text
) ENGINE=MyISAM DEFAULT CHARSET=latin1
alter table t1 modify v char(10);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` char(10) DEFAULT NULL,
  `c` varchar(10) DEFAULT NULL,
  `t` text
) ENGINE=MyISAM DEFAULT CHARSET=latin1
alter table t1 modify t varchar(10);
Warnings:
Note	1265	Data truncated for column 't' at row 2
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` char(10) DEFAULT NULL,
  `c` varchar(10) DEFAULT NULL,
  `t` varchar(10) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select concat('*',v,'*',c,'*',t,'*') from t1;
concat('*',v,'*',c,'*',t,'*')
*+*+*+ *
*+*+*+         *
drop table t1,t2,t3;
create table t1 (v varchar(10), c char(10), t text, key(v), key(c), key(t(10)));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(10) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text,
  KEY `v` (`v`),
  KEY `c` (`c`),
  KEY `t` (`t`(10))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1;
count(*)
270
insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1)));
select count(*) from t1 where v='a';
count(*)
10
select count(*) from t1 where c='a';
count(*)
10
select count(*) from t1 where t='a';
count(*)
10
select count(*) from t1 where v='a  ';
count(*)
10
select count(*) from t1 where c='a  ';
count(*)
10
select count(*) from t1 where t='a  ';
count(*)
10
select count(*) from t1 where v between 'a' and 'a ';
count(*)
10
select count(*) from t1 where v between 'a' and 'a ' and v between 'a  ' and 'b\n';
count(*)
10
select count(*) from t1 where v like 'a%';
count(*)
11
select count(*) from t1 where c like 'a%';
count(*)
11
select count(*) from t1 where t like 'a%';
count(*)
11
select count(*) from t1 where v like 'a %';
count(*)
9
explain select count(*) from t1 where v='a  ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	13	const	#	Using where; Using index
explain select count(*) from t1 where c='a  ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	c	c	11	const	#	Using where; Using index
explain select count(*) from t1 where t='a  ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	t	t	13	const	#	Using where
explain select count(*) from t1 where v like 'a%';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	v	v	13	NULL	#	Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	13	const	#	Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a  ' and 'b\n';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	13	const	#	Using where; Using index
alter table t1 add unique(v);
ERROR 23000: Duplicate entry '{ ' for key 'v_2'
alter table t1 add key(v);
select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a';
qq
*a*a*a*
*a *a*a *
*a  *a*a  *
*a   *a*a   *
*a    *a*a    *
*a     *a*a     *
*a      *a*a      *
*a       *a*a       *
*a        *a*a        *
*a         *a*a         *
explain select * from t1 where v='a';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v,v_2	#	13	const	#	Using index condition
select v,count(*) from t1 group by v limit 10;
v	count(*)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select v,count(c) from t1 group by v limit 10;
v	count(c)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result v,count(c) from t1 group by v limit 10;
v	count(c)
a	1
a 	10
b     	10
c    	10
d   	10
e  	10
f     	10
g    	10
h	10
i     	10
select c,count(*) from t1 group by c limit 10;
c	count(*)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select c,count(t) from t1 group by c limit 10;
c	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result c,count(t) from t1 group by c limit 10;
c	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select t,count(*) from t1 group by t limit 10;
t	count(*)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select t,count(t) from t1 group by t limit 10;
t	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result t,count(t) from t1 group by t limit 10;
t	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
alter table t1 modify v varchar(300), drop key v, drop key v_2, add key v (v);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(300) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text,
  KEY `c` (`c`),
  KEY `t` (`t`(10)),
  KEY `v` (`v`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1 where v='a';
count(*)
10
select count(*) from t1 where v='a  ';
count(*)
10
select count(*) from t1 where v between 'a' and 'a ';
count(*)
10
select count(*) from t1 where v between 'a' and 'a ' and v between 'a  ' and 'b\n';
count(*)
10
select count(*) from t1 where v like 'a%';
count(*)
11
select count(*) from t1 where v like 'a %';
count(*)
9
explain select count(*) from t1 where v='a  ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	303	const	#	Using where; Using index
explain select count(*) from t1 where v like 'a%';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	v	v	303	NULL	#	Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	303	const	#	Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a  ' and 'b\n';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	303	const	#	Using where; Using index
explain select * from t1 where v='a';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	303	const	#	Using index condition
select v,count(*) from t1 group by v limit 10;
v	count(*)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
alter table t1 drop key v, add key v (v(30));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(300) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text,
  KEY `c` (`c`),
  KEY `t` (`t`(10)),
  KEY `v` (`v`(30))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1 where v='a';
count(*)
10
select count(*) from t1 where v='a  ';
count(*)
10
select count(*) from t1 where v between 'a' and 'a ';
count(*)
10
select count(*) from t1 where v between 'a' and 'a ' and v between 'a  ' and 'b\n';
count(*)
10
select count(*) from t1 where v like 'a%';
count(*)
11
select count(*) from t1 where v like 'a %';
count(*)
9
explain select count(*) from t1 where v='a  ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	33	const	#	Using where
explain select count(*) from t1 where v like 'a%';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	v	v	33	NULL	#	Using where
explain select count(*) from t1 where v between 'a' and 'a ';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	33	const	#	Using where
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a  ' and 'b\n';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	33	const	#	Using where
explain select * from t1 where v='a';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	v	v	33	const	#	Using where
select v,count(*) from t1 group by v limit 10;
v	count(*)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
alter table t1 modify v varchar(600), drop key v, add key v (v);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(600) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text,
  KEY `c` (`c`),
  KEY `t` (`t`(10)),
  KEY `v` (`v`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select v,count(*) from t1 group by v limit 10;
v	count(*)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
select sql_big_result v,count(t) from t1 group by v limit 10;
v	count(t)
a	1
a	10
b	10
c	10
d	10
e	10
f	10
g	10
h	10
i	10
drop table t1;
create table t1 (a char(10), unique (a));
insert into t1 values ('a   ');
insert into t1 values ('a ');
ERROR 23000: Duplicate entry 'a' for key 'a'
alter table t1 modify a varchar(10);
insert into t1 values ('a '),('a  '),('a   '),('a         ');
ERROR 23000: Duplicate entry 'a ' for key 'a'
insert into t1 values ('a     ');
ERROR 23000: Duplicate entry 'a     ' for key 'a'
insert into t1 values ('a          ');
ERROR 23000: Duplicate entry 'a         ' for key 'a'
insert into t1 values ('a ');
ERROR 23000: Duplicate entry 'a ' for key 'a'
update t1 set a='a  ' where a like 'a%';
select concat(a,'.') from t1;
concat(a,'.')
a  .
update t1 set a='abc    ' where a like 'a ';
select concat(a,'.') from t1;
concat(a,'.')
a  .
update t1 set a='a      ' where a like 'a %';
select concat(a,'.') from t1;
concat(a,'.')
a      .
update t1 set a='a  ' where a like 'a      ';
select concat(a,'.') from t1;
concat(a,'.')
a  .
drop table t1;
create table t1 (v varchar(10), c char(10), t text, key(v(5)), key(c(5)), key(t(5)));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(10) DEFAULT NULL,
  `c` char(10) DEFAULT NULL,
  `t` text,
  KEY `v` (`v`(5)),
  KEY `c` (`c`(5)),
  KEY `t` (`t`(5))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 (v char(10) character set utf8);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` char(10) CHARACTER SET utf8 DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 (v varchar(10), c char(10)) row_format=fixed;
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `v` varchar(10) DEFAULT NULL,
  `c` char(10) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1 ROW_FORMAT=FIXED
insert into t1 values('a','a'),('a ','a ');
select concat('*',v,'*',c,'*') from t1;
concat('*',v,'*',c,'*')
*a*a*
*a *a*
drop table t1;
create table t1 (v varchar(65530), key(v(10)));
insert into t1 values(repeat('a',65530));
select length(v) from t1 where v=repeat('a',65530);
length(v)
65530
drop table t1;
create table t1(a int, b varchar(12), key ba(b, a));
insert into t1 values (1, 'A'), (20, NULL);
explain select * from t1 where a=20 and b is null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	ba	ba	20	const,const	1	Using where; Using index
select * from t1 where a=20 and b is null;
a	b
20	NULL
drop table t1;
#
#
drop database if exists world;
CREATE DATABASE world;
use world;
CREATE TABLE Country (
Code char(3) NOT NULL default '',
Name char(52) NOT NULL default '',
SurfaceArea float(10,2) NOT NULL default '0.00',
Population int(11) NOT NULL default '0',
Capital int(11) default NULL,
PRIMARY KEY  (Code),
UNIQUE INDEX (Name)
);
CREATE TABLE City (
ID int(11) NOT NULL auto_increment,
Name char(35) NOT NULL default '',
Country char(3) NOT NULL default '',
Population int(11) NOT NULL default '0',
PRIMARY KEY  (ID),
INDEX (Population),
INDEX (Country) 
);
CREATE TABLE CountryLanguage (
Country char(3) NOT NULL default '',
Language char(30) NOT NULL default '',
Percentage float(3,1) NOT NULL default '0.0',
PRIMARY KEY  (Country, Language),
INDEX (Percentage)
);
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'F'))
AND (Population > 101000 AND Population < 102000);
ID	Name	Country	Population
637	Mit Ghamr	EGY	101801
707	Marbella	ESP	101144
3792	Tartu	EST	101246
4032	Cambridge	USA	101355
explain
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'F'))
AND (Population > 101000 AND Population < 102000);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	City	range	Population,Country	Population	4	NULL	#	Using index condition; Using where; Rowid-ordered scan
explain
SELECT  * FROM City 
WHERE (Name < 'Ac' AND (Country > 'A' AND Country < 'B')) OR
(Name BETWEEN 'P' AND 'Pb' AND (Population > 101000 AND Population < 110000));
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	City	index_merge	Population,Country	Country,Population	3,4	NULL	#	Using sort_union(Country,Population); Using where
SELECT  * FROM City 
WHERE (Name < 'Ac' AND (Country > 'A' AND Country < 'B')) OR
(Name BETWEEN 'P' AND 'Pb' AND (Population > 101000 AND Population < 110000));
ID	Name	Country	Population
65	Abu Dhabi	ARE	398695
168	Pabna	BGD	103277
189	Parakou	BEN	103577
750	Paarl	ZAF	105768
2865	Pak Pattan	PAK	107800
SELECT * FROM City
WHERE Name LIKE 'M%' AND Population > 7000000;
ID	Name	Country	Population
1024	Mumbai (Bombay)	IND	10500000
3580	Moscow	RUS	8389200
explain
SELECT * FROM City
WHERE Name LIKE 'M%' AND Population > 7000000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	City	range	Population	Population	4	NULL	#	Using index condition; Using where; Rowid-ordered scan
explain 
SELECT * FROM City 
WHERE Name BETWEEN 'G' AND 'K' AND Population > 500000 AND Country LIKE 'C%';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	City	range	Population,Country	#	#	NULL	#	Using index condition; Using where; Rowid-ordered scan
SELECT * FROM City 
WHERE Name BETWEEN 'G' AND 'K' AND Population > 500000 AND Country LIKE 'C%';
ID	Name	Country	Population
1895	Harbin	CHN	4289800
1904	Jinan	CHN	2278100
1905	Hangzhou	CHN	2190500
1914	Guiyang	CHN	1465200
1916	Hefei	CHN	1369100
1923	Jilin	CHN	1040000
1927	Hohhot	CHN	916700
1928	Handan	CHN	840000
1937	Huainan	CHN	700000
1938	Jixi	CHN	683885
1944	Jinzhou	CHN	570000
1950	Hegang	CHN	520000
explain
SELECT * FROM City 
WHERE  Name BETWEEN 'G' AND 'J' AND Population > 500000 AND Country LIKE 'C%';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	City	range	Population,Country	#	#	NULL	#	Using index condition; Using where; Rowid-ordered scan
SELECT * FROM City 
WHERE  Name BETWEEN 'G' AND 'J' AND Population > 500000 AND Country LIKE 'C%';
ID	Name	Country	Population
1895	Harbin	CHN	4289800
1905	Hangzhou	CHN	2190500
1914	Guiyang	CHN	1465200
1916	Hefei	CHN	1369100
1927	Hohhot	CHN	916700
1928	Handan	CHN	840000
1937	Huainan	CHN	700000
1950	Hegang	CHN	520000
drop database world;
use test;
set @mrr_icp_extra_tmp=@@optimizer_switch;