drop table if exists t1,t2,t3;
CREATE TABLE t1 (S1 INT);
CREATE TABLE t2 (S1 INT);
INSERT INTO t1 VALUES (1);
INSERT INTO t2 VALUES (2);
SELECT * FROM t1 JOIN t2;
S1	S1
1	2
SELECT * FROM t1 INNER JOIN t2;
S1	S1
1	2
SELECT * from t1 JOIN t2 USING (S1);
S1	S1
SELECT * FROM t1 INNER JOIN t2 USING (S1);
S1	S1
SELECT * from t1 CROSS JOIN t2;
S1	S1
1	2
SELECT * from t1 LEFT JOIN t2 USING(S1);
S1	S1
1	NULL
SELECT * from t1 LEFT JOIN t2 ON(t2.S1=2);
S1	S1
1	2
SELECT * from t1 RIGHT JOIN t2 USING(S1);
S1	S1
NULL	2
SELECT * from t1 RIGHT JOIN t2 ON(t1.S1=1);
S1	S1
1	2
drop table t1,t2;
create table t1 (id int primary key);
create table t2 (id int);
insert into t1 values (75);
insert into t1 values (79);
insert into t1 values (78);
insert into t1 values (77);
replace into t1 values (76);
replace into t1 values (76);
insert into t1 values (104);
insert into t1 values (103);
insert into t1 values (102);
insert into t1 values (101);
insert into t1 values (105);
insert into t1 values (106);
insert into t1 values (107);
insert into t2 values (107),(75),(1000);
select t1.id, t2.id from t1, t2 where t2.id = t1.id;
id	id
107	107
75	75
select t1.id, count(t2.id) from t1,t2 where t2.id = t1.id group by t1.id;
id	count(t2.id)
75	1
107	1
select t1.id, count(t2.id) from t1,t2 where t2.id = t1.id group by t2.id;
id	count(t2.id)
75	1
107	1
select t1.id,t2.id from t2 left join t1 on t1.id>=74 and t1.id<=0 where t2.id=75 and t1.id is null;
id	id
NULL	75
explain select t1.id,t2.id from t2 left join t1 on t1.id>=74 and t1.id<=0 where t2.id=75 and t1.id is null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	const	PRIMARY	NULL	NULL	NULL	1	Impossible ON condition
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
explain select t1.id, t2.id from t1, t2 where t2.id = t1.id and t1.id <0 and t1.id > 0;
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
drop table t1,t2;
CREATE TABLE t1 (
id int(11) NOT NULL auto_increment,
token varchar(100) DEFAULT '' NOT NULL,
count int(11) DEFAULT '0' NOT NULL,
qty int(11),
phone char(1) DEFAULT '' NOT NULL,
timestamp datetime DEFAULT '0000-00-00 00:00:00' NOT NULL,
PRIMARY KEY (id),
KEY token (token(15)),
KEY timestamp (timestamp),
UNIQUE token_2 (token(75),count,phone)
);
INSERT INTO t1 VALUES (21,'e45703b64de71482360de8fec94c3ade',3,7800,'n','1999-12-23 17:22:21');
INSERT INTO t1 VALUES (22,'e45703b64de71482360de8fec94c3ade',4,5000,'y','1999-12-23 17:22:21');
INSERT INTO t1 VALUES (18,'346d1cb63c89285b2351f0ca4de40eda',3,13200,'b','1999-12-23 11:58:04');
INSERT INTO t1 VALUES (17,'ca6ddeb689e1b48a04146b1b5b6f936a',4,15000,'b','1999-12-23 11:36:53');
INSERT INTO t1 VALUES (16,'ca6ddeb689e1b48a04146b1b5b6f936a',3,13200,'b','1999-12-23 11:36:53');
INSERT INTO t1 VALUES (26,'a71250b7ed780f6ef3185bfffe027983',5,1500,'b','1999-12-27 09:44:24');
INSERT INTO t1 VALUES (24,'4d75906f3c37ecff478a1eb56637aa09',3,5400,'y','1999-12-23 17:29:12');
INSERT INTO t1 VALUES (25,'4d75906f3c37ecff478a1eb56637aa09',4,6500,'y','1999-12-23 17:29:12');
INSERT INTO t1 VALUES (27,'a71250b7ed780f6ef3185bfffe027983',3,6200,'b','1999-12-27 09:44:24');
INSERT INTO t1 VALUES (28,'a71250b7ed780f6ef3185bfffe027983',3,5400,'y','1999-12-27 09:44:36');
INSERT INTO t1 VALUES (29,'a71250b7ed780f6ef3185bfffe027983',4,17700,'b','1999-12-27 09:45:05');
CREATE TABLE t2 (
id int(11) NOT NULL auto_increment,
category int(11) DEFAULT '0' NOT NULL,
county int(11) DEFAULT '0' NOT NULL,
state int(11) DEFAULT '0' NOT NULL,
phones int(11) DEFAULT '0' NOT NULL,
nophones int(11) DEFAULT '0' NOT NULL,
PRIMARY KEY (id),
KEY category (category,county,state)
);
INSERT INTO t2 VALUES (3,2,11,12,5400,7800);
INSERT INTO t2 VALUES (4,2,25,12,6500,11200);
INSERT INTO t2 VALUES (5,1,37,6,10000,12000);
select a.id, b.category as catid, b.state as stateid, b.county as
countyid from t1 a, t2 b where (a.token =
'a71250b7ed780f6ef3185bfffe027983') and (a.count = b.id);
id	catid	stateid	countyid
27	2	12	11
28	2	12	11
29	2	12	25
26	1	6	37
select a.id, b.category as catid, b.state as stateid, b.county as
countyid from t1 a, t2 b where (a.token =
'a71250b7ed780f6ef3185bfffe027983') and (a.count = b.id) order by a.id;
id	catid	stateid	countyid
26	1	6	37
27	2	12	11
28	2	12	11
29	2	12	25
drop table t1, t2;
create table t1 (a int primary key);
insert into t1 values(1),(2);
select t1.a from t1 as t1 left join t1 as t2 using (a) left join t1 as t3 using (a) left join t1 as t4 using (a) left join t1 as t5 using (a) left join t1 as t6 using (a) left join t1 as t7 using (a) left join t1 as t8 using (a) left join t1 as t9 using (a) left join t1 as t10 using (a) left join t1 as t11 using (a) left join t1 as t12 using (a) left join t1 as t13 using (a) left join t1 as t14 using (a) left join t1 as t15 using (a) left join t1 as t16 using (a) left join t1 as t17 using (a) left join t1 as t18 using (a) left join t1 as t19 using (a) left join t1 as t20 using (a) left join t1 as t21 using (a) left join t1 as t22 using (a) left join t1 as t23 using (a) left join t1 as t24 using (a) left join t1 as t25 using (a) left join t1 as t26 using (a) left join t1 as t27 using (a) left join t1 as t28 using (a) left join t1 as t29 using (a) left join t1 as t30 using (a) left join t1 as t31 using (a);
a
1
2
select t1.a from t1 as t1 left join t1 as t2 using (a) left join t1 as t3 using (a) left join t1 as t4 using (a) left join t1 as t5 using (a) left join t1 as t6 using (a) left join t1 as t7 using (a) left join t1 as t8 using (a) left join t1 as t9 using (a) left join t1 as t10 using (a) left join t1 as t11 using (a) left join t1 as t12 using (a) left join t1 as t13 using (a) left join t1 as t14 using (a) left join t1 as t15 using (a) left join t1 as t16 using (a) left join t1 as t17 using (a) left join t1 as t18 using (a) left join t1 as t19 using (a) left join t1 as t20 using (a) left join t1 as t21 using (a) left join t1 as t22 using (a) left join t1 as t23 using (a) left join t1 as t24 using (a) left join t1 as t25 using (a) left join t1 as t26 using (a) left join t1 as t27 using (a) left join t1 as t28 using (a) left join t1 as t29 using (a) left join t1 as t30 using (a) left join t1 as t31 using (a) left join t1 as t32 using (a) left join t1 as t33 using (a) left join t1 as t34 using (a) left join t1 as t35 using (a) left join t1 as t36 using (a) left join t1 as t37 using (a) left join t1 as t38 using (a) left join t1 as t39 using (a) left join t1 as t40 using (a) left join t1 as t41 using (a) left join t1 as t42 using (a) left join t1 as t43 using (a) left join t1 as t44 using (a) left join t1 as t45 using (a) left join t1 as t46 using (a) left join t1 as t47 using (a) left join t1 as t48 using (a) left join t1 as t49 using (a) left join t1 as t50 using (a) left join t1 as t51 using (a) left join t1 as t52 using (a) left join t1 as t53 using (a) left join t1 as t54 using (a) left join t1 as t55 using (a) left join t1 as t56 using (a) left join t1 as t57 using (a) left join t1 as t58 using (a) left join t1 as t59 using (a) left join t1 as t60 using (a) left join t1 as t61 using (a) left join t1 as t62 using (a) left join t1 as t63 using (a) left join t1 as t64 using (a) left join t1 as t65 using (a);
Too many tables. MySQL can only use XX tables in a join
drop table t1;
CREATE TABLE t1 (
a int(11) NOT NULL,
b int(11) NOT NULL,
PRIMARY KEY  (a,b)
) TYPE=MyISAM;
INSERT INTO t1 VALUES (1,1),(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(2,3);
CREATE TABLE t2 (
a int(11) default NULL
) TYPE=MyISAM;
INSERT INTO t2 VALUES (2),(3);
SELECT t1.a,t2.a,b FROM t1,t2 WHERE t1.a=t2.a AND (t1.a=1 OR t1.a=2) AND b>=1 AND b<=3;
a	a	b
2	2	3
DROP TABLE t1, t2;
CREATE TABLE t1 (d DATE NOT NULL);
CREATE TABLE t2 (d DATE NOT NULL);
INSERT INTO t1 (d) VALUES ('2001-08-01'),('0000-00-00');
SELECT * FROM t1 LEFT JOIN t2 USING (d) WHERE t2.d IS NULL;
d	d
2001-08-01	NULL
0000-00-00	NULL
SELECT * from t1 WHERE t1.d IS NULL;
d
0000-00-00
SELECT * FROM t1 WHERE 1/0 IS NULL;
d
2001-08-01
0000-00-00
DROP TABLE t1,t2;
CREATE TABLE t1 (
Document_ID varchar(50) NOT NULL default '',
Contractor_ID varchar(6) NOT NULL default '',
Language_ID char(3) NOT NULL default '',
Expiration_Date datetime default NULL,
Publishing_Date datetime default NULL,
Title text,
Column_ID varchar(50) NOT NULL default '',
PRIMARY KEY  (Language_ID,Document_ID,Contractor_ID)
);
INSERT INTO t1 VALUES ('xep80','1','ger','2001-12-31 20:00:00','2001-11-12 10:58:00','Kartenbestellung - jetzt auch online','anle'),('','999998','',NULL,NULL,NULL,'');
CREATE TABLE t2 (
Contractor_ID char(6) NOT NULL default '',
Language_ID char(3) NOT NULL default '',
Document_ID char(50) NOT NULL default '',
CanRead char(1) default NULL,
Customer_ID int(11) NOT NULL default '0',
PRIMARY KEY  (Contractor_ID,Language_ID,Document_ID,Customer_ID)
);
INSERT INTO t2 VALUES ('5','ger','xep80','1',999999),('1','ger','xep80','1',999999);
CREATE TABLE t3 (
Language_ID char(3) NOT NULL default '',
Column_ID char(50) NOT NULL default '',
Contractor_ID char(6) NOT NULL default '',
CanRead char(1) default NULL,
Active char(1) default NULL,
PRIMARY KEY  (Language_ID,Column_ID,Contractor_ID)
);
INSERT INTO t3 VALUES ('ger','home','1','1','1'),('ger','Test','1','0','0'),('ger','derclu','1','0','0'),('ger','clubne','1','0','0'),('ger','philos','1','0','0'),('ger','clubko','1','0','0'),('ger','clubim','1','1','1'),('ger','progra','1','0','0'),('ger','progvo','1','0','0'),('ger','progsp','1','0','0'),('ger','progau','1','0','0'),('ger','progku','1','0','0'),('ger','progss','1','0','0'),('ger','nachl','1','0','0'),('ger','mitgli','1','0','0'),('ger','mitsu','1','0','0'),('ger','mitbus','1','0','0'),('ger','ergmar','1','1','1'),('ger','home','4','1','1'),('ger','derclu','4','1','1'),('ger','clubne','4','0','0'),('ger','philos','4','1','1'),('ger','clubko','4','1','1'),('ger','clubim','4','1','1'),('ger','progra','4','1','1'),('ger','progvo','4','1','1'),('ger','progsp','4','1','1'),('ger','progau','4','0','0'),('ger','progku','4','1','1'),('ger','progss','4','1','1'),('ger','nachl','4','1','1'),('ger','mitgli','4','0','0'),('ger','mitsu','4','0','0'),('ger','mitbus','4','0','0'),('ger','ergmar','4','1','1'),('ger','progra2','1','0','0'),('ger','archiv','4','1','1'),('ger','anmeld','4','1','1'),('ger','thema','4','1','1'),('ger','edito','4','1','1'),('ger','madis','4','1','1'),('ger','enma','4','1','1'),('ger','madis','1','1','1'),('ger','enma','1','1','1'),('ger','vorsch','4','0','0'),('ger','veranst','4','0','0'),('ger','anle','4','1','1'),('ger','redak','4','1','1'),('ger','nele','4','1','1'),('ger','aukt','4','1','1'),('ger','callcenter','4','1','1'),('ger','anle','1','0','0');
delete from t1 where Contractor_ID='999998';
insert into t1 (Contractor_ID) Values ('999998');
SELECT DISTINCT COUNT(t1.Title) FROM t1,
t2, t3 WHERE 
t1.Document_ID='xep80' AND t1.Contractor_ID='1' AND 
t1.Language_ID='ger' AND '2001-12-21 23:14:24' >= 
Publishing_Date AND '2001-12-21 23:14:24' <= Expiration_Date AND 
t1.Document_ID = t2.Document_ID AND 
t1.Language_ID = t2.Language_ID AND 
t1.Contractor_ID = t2.Contractor_ID AND ( 
t2.Customer_ID = '4'  OR 
t2.Customer_ID = '999999'  OR 
t2.Customer_ID = '1' )AND t2.CanRead 
= '1'  AND t1.Column_ID=t3.Column_ID AND 
t1.Language_ID=t3.Language_ID AND ( 
t3.Contractor_ID = '4'  OR 
t3.Contractor_ID = '999999'  OR 
t3.Contractor_ID = '1') AND 
t3.CanRead='1' AND t3.Active='1';
COUNT(t1.Title)
1
SELECT DISTINCT COUNT(t1.Title) FROM t1,
t2, t3 WHERE 
t1.Document_ID='xep80' AND t1.Contractor_ID='1' AND 
t1.Language_ID='ger' AND '2001-12-21 23:14:24' >= 
Publishing_Date AND '2001-12-21 23:14:24' <= Expiration_Date AND 
t1.Document_ID = t2.Document_ID AND 
t1.Language_ID = t2.Language_ID AND 
t1.Contractor_ID = t2.Contractor_ID AND ( 
t2.Customer_ID = '4'  OR 
t2.Customer_ID = '999999'  OR 
t2.Customer_ID = '1' )AND t2.CanRead 
= '1'  AND t1.Column_ID=t3.Column_ID AND 
t1.Language_ID=t3.Language_ID AND ( 
t3.Contractor_ID = '4'  OR 
t3.Contractor_ID = '999999'  OR 
t3.Contractor_ID = '1') AND 
t3.CanRead='1' AND t3.Active='1';
COUNT(t1.Title)
1
drop table t1,t2,t3;
CREATE TABLE t1 (
t1_id int(11) default NULL,
t2_id int(11) default NULL,
type enum('Cost','Percent') default NULL,
cost_unit enum('Cost','Unit') default NULL,
min_value double default NULL,
max_value double default NULL,
t3_id int(11) default NULL,
item_id int(11) default NULL
) TYPE=MyISAM;
INSERT INTO t1 VALUES (12,5,'Percent','Cost',-1,0,-1,-1),(14,4,'Percent','Cost',-1,0,-1,-1),(18,5,'Percent','Cost',-1,0,-1,-1),(19,4,'Percent','Cost',-1,0,-1,-1),(20,5,'Percent','Cost',100,-1,22,291),(21,5,'Percent','Cost',100,-1,18,291),(22,1,'Percent','Cost',100,-1,6,291),(23,1,'Percent','Cost',100,-1,21,291),(24,1,'Percent','Cost',100,-1,9,291),(25,1,'Percent','Cost',100,-1,4,291),(26,1,'Percent','Cost',100,-1,20,291),(27,4,'Percent','Cost',100,-1,7,202),(28,1,'Percent','Cost',50,-1,-1,137),(29,2,'Percent','Cost',100,-1,4,354),(30,2,'Percent','Cost',100,-1,9,137),(93,2,'Cost','Cost',-1,10000000,-1,-1);
CREATE TABLE t2 (
id int(10) unsigned NOT NULL auto_increment,
name varchar(255) default NULL,
PRIMARY KEY  (id)
) TYPE=MyISAM;
INSERT INTO t2 VALUES (1,'s1'),(2,'s2'),(3,'s3'),(4,'s4'),(5,'s5');
select t1.*, t2.*  from t1, t2 where t2.id=t1.t2_id limit 2;
t1_id	t2_id	type	cost_unit	min_value	max_value	t3_id	item_id	id	name
22	1	Percent	Cost	100	-1	6	291	1	s1
23	1	Percent	Cost	100	-1	21	291	1	s1
drop table t1,t2;
CREATE TABLE t1 (
siteid varchar(25) NOT NULL default '',
emp_id varchar(30) NOT NULL default '',
rate_code varchar(10) default NULL,
UNIQUE KEY site_emp (siteid,emp_id),
KEY siteid (siteid)
) TYPE=MyISAM;
INSERT INTO t1 VALUES ('rivercats','psmith','cust'), ('rivercats','KWalker','cust');
CREATE TABLE t2 (
siteid varchar(25) NOT NULL default '',
rate_code varchar(10) NOT NULL default '',
base_rate float NOT NULL default '0',
PRIMARY KEY  (siteid,rate_code),
FULLTEXT KEY rate_code (rate_code)
) TYPE=MyISAM;
INSERT INTO t2 VALUES ('rivercats','cust',20);
SELECT emp.rate_code, lr.base_rate FROM t1 AS emp LEFT JOIN t2 AS lr USING (siteid, rate_code) WHERE emp.emp_id = 'psmith' AND lr.siteid = 'rivercats';
rate_code	base_rate
cust	20
SELECT emp.rate_code, lr.base_rate FROM t1 AS emp LEFT JOIN t2 AS lr USING (siteid, rate_code) WHERE lr.siteid = 'rivercats' AND emp.emp_id = 'psmith';
rate_code	base_rate
cust	20
drop table t1,t2;
CREATE TABLE t1 (ID INTEGER NOT NULL PRIMARY KEY, Value1 VARCHAR(255));
CREATE TABLE t2 (ID INTEGER NOT NULL PRIMARY KEY, Value2 VARCHAR(255));
INSERT INTO t1 VALUES (1, 'A');
INSERT INTO t2 VALUES (1, 'B');
SELECT * FROM t1 NATURAL JOIN t2 WHERE 1 AND (Value1 = 'A' AND Value2 <> 'B');
ID	Value1	ID	Value2
SELECT * FROM t1 NATURAL JOIN t2 WHERE 1 AND Value1 = 'A' AND Value2 <> 'B';
ID	Value1	ID	Value2
SELECT * FROM t1 NATURAL JOIN t2 WHERE (Value1 = 'A' AND Value2 <> 'B') AND 1;
ID	Value1	ID	Value2
drop table t1,t2;
create table t1 (i int);
create table t2 (i int);
create table t3 (i int);
insert into t1 values(1),(2);
insert into t2 values(2),(3);
insert into t3 values (2),(4);
select * from t1 natural left join t2;
i	i
1	NULL
2	2
select * from t1 left join t2 on (t1.i=t2.i);
i	i
1	NULL
2	2
select * from t1 natural left join t2 natural left join t3;
i	i	i
1	NULL	NULL
2	2	2
select * from t1 left join t2 on (t1.i=t2.i) left join t3 on (t2.i=t3.i);
i	i	i
1	NULL	NULL
2	2	2
select * from t3 natural right join t2;
i	i
2	2
NULL	3
select * from t3 right join t2 on (t3.i=t2.i);
i	i
2	2
NULL	3
select * from t3 natural right join t2 natural right join t1;
i	i	i
NULL	NULL	1
2	2	2
select * from t3 right join t2 on (t3.i=t2.i) right join t1 on (t2.i=t1.i);
i	i	i
NULL	NULL	1
2	2	2
select * from t1,t2 natural left join t3 order by t1.i,t2.i,t3.i;
i	i	i
1	2	2
1	3	NULL
2	2	2
2	3	NULL
select * from t1,t2 left join t3 on (t2.i=t3.i) order by t1.i,t2.i,t3.i;
i	i	i
1	2	2
1	3	NULL
2	2	2
2	3	NULL
select t1.i,t2.i,t3.i from t2 natural left join t3,t1 order by t1.i,t2.i,t3.i;
i	i	i
1	2	2
1	3	NULL
2	2	2
2	3	NULL
select t1.i,t2.i,t3.i from t2 left join t3 on (t2.i=t3.i),t1 order by t1.i,t2.i,t3.i;
i	i	i
1	2	2
1	3	NULL
2	2	2
2	3	NULL
select * from t1,t2 natural right join t3 order by t1.i,t2.i,t3.i;
i	i	i
1	NULL	4
1	2	2
2	NULL	4
2	2	2
select * from t1,t2 right join t3 on (t2.i=t3.i) order by t1.i,t2.i,t3.i;
i	i	i
1	NULL	4
1	2	2
2	NULL	4
2	2	2
select t1.i,t2.i,t3.i from t2 natural right join t3,t1 order by t1.i,t2.i,t3.i;
i	i	i
1	NULL	4
1	2	2
2	NULL	4
2	2	2
select t1.i,t2.i,t3.i from t2 right join t3 on (t2.i=t3.i),t1 order by t1.i,t2.i,t3.i;
i	i	i
1	NULL	4
1	2	2
2	NULL	4
2	2	2
drop table t1,t2,t3;