drop table if exists t1,t2,t3;
CREATE TABLE t1 (
id int(6) DEFAULT '0' NOT NULL,
idservice int(5),
clee char(20) NOT NULL,
flag char(1),
KEY id (id),
PRIMARY KEY (clee)
);
INSERT INTO t1 VALUES (2,4,'6067169d','Y');
INSERT INTO t1 VALUES (2,5,'606716d1','Y');
INSERT INTO t1 VALUES (2,1,'606717c1','Y');
INSERT INTO t1 VALUES (3,1,'6067178d','Y');
INSERT INTO t1 VALUES (2,6,'60671515','Y');
INSERT INTO t1 VALUES (2,7,'60671569','Y');
INSERT INTO t1 VALUES (2,3,'dd','Y');
CREATE TABLE t2 (
id int(6) NOT NULL auto_increment,
description varchar(40) NOT NULL,
idform varchar(40),
ordre int(6) unsigned DEFAULT '0' NOT NULL,
image varchar(60),
PRIMARY KEY (id),
KEY id (id,ordre)
);
INSERT INTO t2 VALUES (1,'Emettre un appel d''offres','en_construction.html',10,'emettre.gif');
INSERT INTO t2 VALUES (2,'Emettre des soumissions','en_construction.html',20,'emettre.gif');
INSERT INTO t2 VALUES (7,'Liste des t2','t2_liste_form.phtml',51060,'link.gif');
INSERT INTO t2 VALUES (8,'Consulter les soumissions','consulter_soumissions.phtml',200,'link.gif');
INSERT INTO t2 VALUES (9,'Ajouter un type de materiel','typeMateriel_ajoute_form.phtml',51000,'link.gif');
INSERT INTO t2 VALUES (10,'Lister/modifier un type de materiel','typeMateriel_liste_form.phtml',51010,'link.gif');
INSERT INTO t2 VALUES (3,'Créer une fiche de client','clients_ajoute_form.phtml',40000,'link.gif');
INSERT INTO t2 VALUES (4,'Modifier des clients','en_construction.html',40010,'link.gif');
INSERT INTO t2 VALUES (5,'Effacer des clients','en_construction.html',40020,'link.gif');
INSERT INTO t2 VALUES (6,'Ajouter un service','t2_ajoute_form.phtml',51050,'link.gif');
select t1.id,t1.idservice,t2.ordre,t2.description  from t1, t2 where t1.id = 2   and t1.idservice = t2.id  order by t2.ordre;
id	idservice	ordre	description
2	1	10	Emettre un appel d'offres
2	3	40000	Créer une fiche de client
2	4	40010	Modifier des clients
2	5	40020	Effacer des clients
2	6	51050	Ajouter un service
2	7	51060	Liste des t2
drop table t1,t2;
create table t1 (first char(10),last char(10));
insert into t1 values ("Michael","Widenius");
insert into t1 values ("Allan","Larsson");
insert into t1 values ("David","Axmark");
select concat(first," ",last) as name from t1 order by name;
name
Allan Larsson
David Axmark
Michael Widenius
select concat(last," ",first) as name from t1 order by name;
name
Axmark David
Larsson Allan
Widenius Michael
drop table t1;
create table t1 (i int);
insert into t1 values(1),(2),(1),(2),(1),(2),(3);
select distinct i from t1;
i
1
2
3
select distinct i from t1 order by rand(5);
i
1
3
2
select distinct i from t1 order by i desc;
i
3
2
1
select distinct i from t1 order by 1-i;
i
3
2
1
select distinct i from t1 order by mod(i,2),i;
i
2
1
3
drop table t1;
create table t1 (id int not null,col1 int not null,col2 int not null,index(col1));
insert into t1 values(1,2,2),(2,2,1),(3,1,2),(4,1,1),(5,1,4),(6,2,3),(7,3,1),(8,2,4);
select * from t1 order by col1,col2;
id	col1	col2
4	1	1
3	1	2
5	1	4
2	2	1
1	2	2
6	2	3
8	2	4
7	3	1
select col1 from t1 order by id;
col1
2
2
1
1
1
2
3
2
select col1 as id from t1 order by t1.id;
id
1
1
1
2
2
2
2
3
select concat(col1) as id from t1 order by t1.id;
id
2
2
1
1
1
2
3
2
drop table t1;
CREATE TABLE t1 (id int auto_increment primary key,aika varchar(40),aikakentta  timestamp);
insert into t1 (aika) values ('Keskiviikko');
insert into t1 (aika) values ('Tiistai');
insert into t1 (aika) values ('Maanantai');
insert into t1 (aika) values ('Sunnuntai');
SELECT FIELD(SUBSTRING(t1.aika,1,2),'Ma','Ti','Ke','To','Pe','La','Su') AS test FROM t1 ORDER by test;
test
1
2
3
7
drop table t1;
CREATE TABLE t1
(
a          int unsigned       NOT NULL,
b          int unsigned       NOT NULL,
c          int unsigned       NOT NULL,
UNIQUE(a),
INDEX(b),
INDEX(c)
);
CREATE TABLE t2
(
c          int unsigned       NOT NULL,
i          int unsigned       NOT NULL,
INDEX(c)
);
CREATE TABLE t3
(
c          int unsigned       NOT NULL,
v          varchar(64),
INDEX(c)
);
INSERT INTO t1 VALUES (1,1,1);
INSERT INTO t1 VALUES (2,1,2);
INSERT INTO t1 VALUES (3,2,1);
INSERT INTO t1 VALUES (4,2,2);
INSERT INTO t2 VALUES (1,50);
INSERT INTO t2 VALUES (2,25);
INSERT INTO t3 VALUES (1,'123 Park Place');
INSERT INTO t3 VALUES (2,'453 Boardwalk');
SELECT    a,b,if(b = 1,i,if(b = 2,v,''))
FROM      t1
LEFT JOIN t2 USING(c)
LEFT JOIN t3 ON t3.c = t1.c;
a	b	if(b = 1,i,if(b = 2,v,''))
1	1	50
2	1	25
3	2	123 Park Place
4	2	453 Boardwalk
SELECT    a,b,if(b = 1,i,if(b = 2,v,''))
FROM      t1
LEFT JOIN t2 USING(c)
LEFT JOIN t3 ON t3.c = t1.c
ORDER BY a;
a	b	if(b = 1,i,if(b = 2,v,''))
1	1	50
2	1	25
3	2	123 Park Place
4	2	453 Boardwalk
drop table t1,t2,t3;
create table t1 (ID int not null primary key, TransactionID int not null);
insert into t1 (ID, TransactionID) values  (1,  87), (2,  89), (3,  92), (4,  94), (5,  486), (6,  490), (7,  753), (9,  828), (10, 832), (11, 834), (12, 840);
create table t2 (ID int not null primary key, GroupID int not null);
insert into t2 (ID, GroupID) values (87,  87), (89,  89), (92,  92), (94,  94), (486, 486), (490, 490),(753, 753), (828, 828), (832, 832), (834, 834), (840, 840);
create table t3 (ID int not null primary key, DateOfAction date not null);
insert into t3 (ID, DateOfAction) values  (87,  '1999-07-19'), (89,  '1999-07-19'), (92,  '1999-07-19'), (94,  '1999-07-19'), (486, '1999-07-18'), (490, '2000-03-27'), (753, '2000-03-28'), (828, '1999-07-27'), (832, '1999-07-27'),(834, '1999-07-27'), (840, '1999-07-27');
select t3.DateOfAction, t1.TransactionID from t1 join t2 join t3 where t2.ID = t1.TransactionID and t3.ID = t2.GroupID order by t3.DateOfAction, t1.TransactionID;
DateOfAction	TransactionID
1999-07-18	486
1999-07-19	87
1999-07-19	89
1999-07-19	92
1999-07-19	94
1999-07-27	828
1999-07-27	832
1999-07-27	834
1999-07-27	840
2000-03-27	490
2000-03-28	753
select t3.DateOfAction, t1.TransactionID from t1 join t2 join t3 where t2.ID = t1.TransactionID and t3.ID = t2.GroupID order by t1.TransactionID,t3.DateOfAction;
DateOfAction	TransactionID
1999-07-19	87
1999-07-19	89
1999-07-19	92
1999-07-19	94
1999-07-18	486
2000-03-27	490
2000-03-28	753
1999-07-27	828
1999-07-27	832
1999-07-27	834
1999-07-27	840
drop table t1,t2,t3;
CREATE TABLE t1 (
member_id int(11) NOT NULL auto_increment,
inschrijf_datum varchar(20) NOT NULL default '',
lastchange_datum varchar(20) NOT NULL default '',
nickname varchar(20) NOT NULL default '',
password varchar(8) NOT NULL default '',
voornaam varchar(30) NOT NULL default '',
tussenvoegsels varchar(10) NOT NULL default '',
achternaam varchar(50) NOT NULL default '',
straat varchar(100) NOT NULL default '',
postcode varchar(10) NOT NULL default '',
wijk varchar(40) NOT NULL default '',
plaats varchar(50) NOT NULL default '',
telefoon varchar(10) NOT NULL default '',
geboortedatum date NOT NULL default '0000-00-00',
geslacht varchar(5) NOT NULL default '',
email varchar(80) NOT NULL default '',
uin varchar(15) NOT NULL default '',
homepage varchar(100) NOT NULL default '',
internet varchar(15) NOT NULL default '',
scherk varchar(30) NOT NULL default '',
favo_boek varchar(50) NOT NULL default '',
favo_tijdschrift varchar(50) NOT NULL default '',
favo_tv varchar(50) NOT NULL default '',
favo_eten varchar(50) NOT NULL default '',
favo_muziek varchar(30) NOT NULL default '',
info text NOT NULL,
ipnr varchar(30) NOT NULL default '',
PRIMARY KEY  (member_id)
) TYPE=MyISAM PACK_KEYS=1;
insert into t1 (member_id) values (1),(2),(3);
select member_id, nickname, voornaam FROM t1
ORDER by lastchange_datum DESC LIMIT 2;
member_id	nickname	voornaam
1		
2		
drop table t1;
create table t1 (a int not null, b int, c varchar(10), key (a, b, c));
insert into t1 values (1, NULL, NULL), (1, NULL, 'b'), (1, 1, NULL), (1, 1, 'b'), (1, 1, 'b'), (2, 1, 'a'), (2, 1, 'b'), (2, 2, 'a'), (2, 2, 'b'), (2, 3, 'c'),(1,3,'b');
explain select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	20	NULL	2	Using where; Using index
select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc;
a	b	c
1	NULL	b
explain select * from t1 where a >= 1 and a < 3 order by a desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	4	NULL	10	Using where; Using index
select * from t1 where a >= 1 and a < 3 order by a desc;
a	b	c
2	3	c
2	2	b
2	2	a
2	1	b
2	1	a
1	3	b
1	1	b
1	1	b
1	1	NULL
1	NULL	b
1	NULL	NULL
explain select * from t1 where a = 1 order by a desc, b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	a	a	4	const	5	Using where; Using index
select * from t1 where a = 1 order by a desc, b desc;
a	b	c
1	3	b
1	1	b
1	1	b
1	1	NULL
1	NULL	b
1	NULL	NULL
explain select * from t1 where a = 1 and b is null order by a desc, b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	a	a	9	const,const	2	Using where; Using index; Using filesort
select * from t1 where a = 1 and b is null order by a desc, b desc;
a	b	c
1	NULL	NULL
1	NULL	b
explain select * from t1 where a >= 1 and a < 3 and b >0 order by a desc,b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	9	NULL	8	Using where; Using index
explain select * from t1 where a = 2 and b >0 order by a desc,b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	9	NULL	5	Using where; Using index
explain select * from t1 where a = 2 and b is null order by a desc,b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	a	a	9	const,const	1	Using where; Using index; Using filesort
explain select * from t1 where a = 2 and (b is null or b > 0) order by a
desc,b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	9	NULL	6	Using where; Using index
explain select * from t1 where a = 2 and b > 0 order by a desc,b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	9	NULL	5	Using where; Using index
explain select * from t1 where a = 2 and b < 2 order by a desc,b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	9	NULL	2	Using where; Using index
explain select * from t1 where a = 1 order by b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	a	a	4	const	5	Using where; Using index
select * from t1 where a = 1 order by b desc;
a	b	c
1	3	b
1	1	b
1	1	b
1	1	NULL
1	NULL	b
1	NULL	NULL
alter table t1 modify b int not null, modify c varchar(10) not null;
Warnings:
Warning	1264	Data truncated for column 'b' at row 1
Warning	1264	Data truncated for column 'c' at row 1
Warning	1264	Data truncated for column 'b' at row 2
Warning	1264	Data truncated for column 'c' at row 3
explain select * from t1 order by a, b, c;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	18	NULL	11	Using index
select * from t1 order by a, b, c;
a	b	c
1	0	
1	0	b
1	1	
1	1	b
1	1	b
1	3	b
2	1	a
2	1	b
2	2	a
2	2	b
2	3	c
explain select * from t1 order by a desc, b desc, c desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	a	18	NULL	11	Using index
select * from t1 order by a desc, b desc, c desc;
a	b	c
2	3	c
2	2	b
2	2	a
2	1	b
2	1	a
1	3	b
1	1	b
1	1	b
1	1	
1	0	b
1	0	
explain select * from t1 where (a = 1 and b = 1 and c = 'b') or (a > 2) order by a desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	18	NULL	3	Using where; Using index
select * from t1 where (a = 1 and b = 1 and c = 'b') or (a > 2) order by a desc;
a	b	c
1	1	b
1	1	b
explain select * from t1 where a < 2 and b <= 1 order by a desc, b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	4	NULL	6	Using where; Using index
select * from t1 where a < 2 and b <= 1 order by a desc, b desc;
a	b	c
1	1	b
1	1	b
1	1	
1	0	b
1	0	
select count(*) from t1 where a < 5 and b > 0;
count(*)
9
select * from t1 where a < 5 and b > 0 order by a desc,b desc;
a	b	c
2	3	c
2	2	b
2	2	a
2	1	b
2	1	a
1	3	b
1	1	b
1	1	b
1	1	
explain select * from t1 where a between 1 and 3 and b <= 1 order by a desc, b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	8	NULL	10	Using where; Using index
select * from t1 where a between 1 and 3 and b <= 1 order by a desc, b desc;
a	b	c
2	1	b
2	1	a
1	1	b
1	1	b
1	1	
1	0	b
1	0	
explain select * from t1 where a between 0 and 1 order by a desc, b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	a	a	4	NULL	5	Using where; Using index
select * from t1 where a between 0 and 1 order by a desc, b desc;
a	b	c
1	3	b
1	1	b
1	1	b
1	1	
1	0	b
1	0	
drop table t1;
CREATE TABLE t1 (
gid int(10) unsigned NOT NULL auto_increment,
cid smallint(5) unsigned NOT NULL default '0',
PRIMARY KEY  (gid),
KEY component_id (cid)
) TYPE=MyISAM;
INSERT INTO t1 VALUES (103853,108),(103867,108),(103962,108),(104505,108),(104619,108),(104620,108);
ALTER TABLE t1 add skr int(10) not null;
CREATE TABLE t2 (
gid int(10) unsigned NOT NULL default '0',
uid smallint(5) unsigned NOT NULL default '1',
sid tinyint(3) unsigned NOT NULL default '1',
PRIMARY KEY  (gid),
KEY uid (uid),
KEY status_id (sid)
) TYPE=MyISAM;
INSERT INTO t2 VALUES (103853,250,5),(103867,27,5),(103962,27,5),(104505,117,5),(104619,75,5),(104620,15,5);
CREATE TABLE t3 (
uid smallint(6) NOT NULL auto_increment,
PRIMARY KEY  (uid)
) TYPE=MyISAM;
INSERT INTO t3 VALUES (1),(15),(27),(75),(117),(250);
ALTER TABLE t3 add skr int(10) not null;
select t1.gid, t2.sid, t3.uid from t2, t1, t3 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid;
gid	sid	uid
104620	5	15
103867	5	27
103962	5	27
104619	5	75
104505	5	117
103853	5	250
select t1.gid, t2.sid, t3.uid from t3, t2, t1 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid;
gid	sid	uid
104620	5	15
103867	5	27
103962	5	27
104619	5	75
104505	5	117
103853	5	250
EXPLAIN select t1.gid, t2.sid, t3.uid from t3, t2, t1 where t2.gid = t1.gid and t2.uid = t3.uid order by t1.gid, t3.uid;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	6	Using index
1	SIMPLE	t2	eq_ref	PRIMARY,uid	PRIMARY	4	test.t1.gid	1	
1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	2	test.t2.uid	1	Using where; Using index
EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.gid = t3.uid order by t1.gid,t3.skr;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t3	ALL	PRIMARY	NULL	NULL	NULL	6	Using temporary; Using filesort
1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t3.uid	1	Using where; Using index
EXPLAIN SELECT t1.gid, t2.sid, t3.uid from t2, t1, t3 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	6	Using index; Using temporary; Using filesort
1	SIMPLE	t2	eq_ref	PRIMARY,uid	PRIMARY	4	test.t1.gid	1	
1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	2	test.t2.uid	1	Using where; Using index
EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.gid = t3.uid order by t3.skr,t1.gid;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t3	ALL	PRIMARY	NULL	NULL	NULL	6	Using temporary; Using filesort
1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t3.uid	1	Using where; Using index
EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.skr = t3.uid order by t1.gid,t3.skr;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	6	Using temporary; Using filesort
1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	2	test.t1.skr	1	Using where
drop table t1,t2,t3;
CREATE TABLE t1 (
`titre` char(80) NOT NULL default '',
`numeropost` mediumint(8) unsigned NOT NULL auto_increment,
`date` datetime NOT NULL default '0000-00-00 00:00:00',
`auteur` char(35) NOT NULL default '',
`icone` tinyint(2) unsigned NOT NULL default '0',
`lastauteur` char(35) NOT NULL default '',
`nbrep` smallint(6) unsigned NOT NULL default '0',
`dest` char(35) NOT NULL default '',
`lu` tinyint(1) unsigned NOT NULL default '0',
`vue` mediumint(8) unsigned NOT NULL default '0',
`ludest` tinyint(1) unsigned NOT NULL default '0',
`ouvert` tinyint(1) unsigned NOT NULL default '1',
PRIMARY KEY  (`numeropost`),
KEY `date` (`date`),
KEY `dest` (`dest`,`ludest`),
KEY `auteur` (`auteur`,`lu`),
KEY `auteur_2` (`auteur`,`date`),
KEY `dest_2` (`dest`,`date`)
) CHECKSUM=1;
CREATE TABLE t2 (
`numeropost` mediumint(8) unsigned NOT NULL default '0',
`pseudo` char(35) NOT NULL default '',
PRIMARY KEY  (`numeropost`,`pseudo`),
KEY `pseudo` (`pseudo`)
);
INSERT INTO t1 (titre,auteur,dest) VALUES ('test','joce','bug');
INSERT INTO t2 (numeropost,pseudo) VALUES (1,'joce'),(1,'bug');
SELECT titre,t1.numeropost,auteur,icone,nbrep,0,date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30;
titre	numeropost	auteur	icone	nbrep	0	date	vue	ouvert	lastauteur	dest
test	1	joce	0	0	0	0000-00-00 00:00:00	0	1		bug
SELECT titre,t1.numeropost,auteur,icone,nbrep,'0',date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30;
titre	numeropost	auteur	icone	nbrep	0	date	vue	ouvert	lastauteur	dest
test	1	joce	0	0	0	0000-00-00 00:00:00	0	1		bug
drop table t1,t2;
CREATE TABLE t1 (a int, b int);
INSERT INTO t1 VALUES (1, 2);
INSERT INTO t1 VALUES (3, 4);
INSERT INTO t1 VALUES (5, NULL);
SELECT * FROM t1 ORDER BY b;
a	b
5	NULL
1	2
3	4
SELECT * FROM t1 ORDER BY b DESC;
a	b
3	4
1	2
5	NULL
SELECT * FROM t1 ORDER BY (a + b);
a	b
5	NULL
1	2
3	4
SELECT * FROM t1 ORDER BY (a + b) DESC;
a	b
3	4
1	2
5	NULL
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 WHERE FieldKey = '1' ORDER BY LongVal;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	FieldKey,LongField,StringField	LongField	36	const	3	Using where
SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal;
FieldKey	LongVal	StringVal
1	0	2
1	1	3
1	2	1
EXPLAIN SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY LongVal;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	FieldKey,LongField,StringField	FieldKey	36	NULL	4	Using where; Using filesort
SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY LongVal;
FieldKey	LongVal	StringVal
3	1	2
3	2	1
3	3	3
EXPLAIN SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY FieldKey, LongVal;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	FieldKey,LongField,StringField	LongField	36	NULL	4	Using where
SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY FieldKey, LongVal;
FieldKey	LongVal	StringVal
3	1	2
3	2	1
3	3	3
DROP TABLE t1;
CREATE TABLE t1 (a INT, b INT);
SET @id=0;
UPDATE t1 SET a=0 ORDER BY (a=@id), b;
DROP TABLE t1;
