func_str.result

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

select t1.*,t2.* from t1 left join t2 on (t1.b=t2.b)
where coercibility(t2.a) = 2 order by t1.a,t2.a;
a	b	a	b
1	1	NULL	NULL
2	2	2	2
DROP TABLE t1, t2;
select SUBSTR('abcdefg',3,2);
SUBSTR('abcdefg',3,2)
cd
select SUBSTRING('abcdefg',3,2);
SUBSTRING('abcdefg',3,2)
cd
select SUBSTR('abcdefg',-3,2) FROM DUAL;
SUBSTR('abcdefg',-3,2)
ef
select SUBSTR('abcdefg',-1,5) FROM DUAL;
SUBSTR('abcdefg',-1,5)
g
select SUBSTR('abcdefg',0,0) FROM DUAL;
SUBSTR('abcdefg',0,0)

select SUBSTR('abcdefg',-1,-1) FROM DUAL;
SUBSTR('abcdefg',-1,-1)

select SUBSTR('abcdefg',1,-1) FROM DUAL;
SUBSTR('abcdefg',1,-1)

create table t7 (s1 char);
select * from t7
where concat(s1 collate latin1_general_ci,s1 collate latin1_swedish_ci) = 'AA';
ERROR HY000: Illegal mix of collations (latin1_general_ci,EXPLICIT) and (latin1_swedish_ci,EXPLICIT) for operation 'concat'
drop table t7;
select substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2),substring_index("1abcd;2abcd;3abcd;4abcd", ';', -2);
substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2)	substring_index("1abcd;2abcd;3abcd;4abcd", ';', -2)
1abcd;2abcd	3abcd;4abcd
explain extended select md5('hello'), sha('abc'), sha1('abc'), soundex(''), 'mood' sounds like 'mud', aes_decrypt(aes_encrypt('abc','1'),'1'),concat('*',space(5),'*'), reverse('abc'), rpad('a',4,'1'), lpad('a',4,'1'),  concat_ws(',','',NULL,'a'),make_set(255,_latin2'a',_latin2'b',_latin2'c'),elt(2,1),locate("a","b",2),format(130,10),char(0),conv(130,16,10),hex(130),binary 'HE', export_set(255,_latin2'y',_latin2'n',_latin2' '),FIELD('b' COLLATE latin1_bin,'A','B'),FIND_IN_SET(_latin1'B',_latin1'a,b,c,d'),collation(conv(130,16,10)), coercibility(conv(130,16,10)),length('\n\t\r\b\0\_\%\\'),bit_length('\n\t\r\b\0\_\%\\'),bit_length('\n\t\r\b\0\_\%\\'),concat('monty',' was here ','again'),length('hello'),char(ascii('h')),ord('h'),quote(1/0),crc32("123"),replace('aaaa','a','b'),insert('txs',2,1,'hi'),left(_latin2'a',1),right(_latin2'a',1),lcase(_latin2'a'),ucase(_latin2'a'),SUBSTR('abcdefg',3,2),substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2),trim(_latin2' a '),ltrim(_latin2' a '),rtrim(_latin2' a '), decode(encode(repeat("a",100000),"monty"),"monty");
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1003	select md5(_latin1'hello') AS `md5('hello')`,sha(_latin1'abc') AS `sha('abc')`,sha(_latin1'abc') AS `sha1('abc')`,soundex(_latin1'') AS `soundex('')`,(soundex(_latin1'mood') = soundex(_latin1'mud')) AS `'mood' sounds like 'mud'`,aes_decrypt(aes_encrypt(_latin1'abc',_latin1'1'),_latin1'1') AS `aes_decrypt(aes_encrypt('abc','1'),'1')`,concat(_latin1'*',repeat(_latin1' ',5),_latin1'*') AS `concat('*',space(5),'*')`,reverse(_latin1'abc') AS `reverse('abc')`,rpad(_latin1'a',4,_latin1'1') AS `rpad('a',4,'1')`,lpad(_latin1'a',4,_latin1'1') AS `lpad('a',4,'1')`,concat_ws(_latin1',',_latin1'',NULL,_latin1'a') AS `concat_ws(',','',NULL,'a')`,make_set(255,_latin2'a',_latin2'b',_latin2'c') AS `make_set(255,_latin2'a',_latin2'b',_latin2'c')`,elt(2,1) AS `elt(2,1)`,locate(_latin1'a',_latin1'b',2) AS `locate("a","b",2)`,format(130,10) AS `format(130,10)`,char(0) AS `char(0)`,conv(130,16,10) AS `conv(130,16,10)`,hex(130) AS `hex(130)`,cast(_latin1'HE' as char charset binary) AS `binary 'HE'`,export_set(255,_latin2'y',_latin2'n',_latin2' ') AS `export_set(255,_latin2'y',_latin2'n',_latin2' ')`,field((_latin1'b' collate latin1_bin),_latin1'A',_latin1'B') AS `FIELD('b' COLLATE latin1_bin,'A','B')`,find_in_set(_latin1'B',_latin1'a,b,c,d') AS `FIND_IN_SET(_latin1'B',_latin1'a,b,c,d')`,collation(conv(130,16,10)) AS `collation(conv(130,16,10))`,coercibility(conv(130,16,10)) AS `coercibility(conv(130,16,10))`,length(_latin1'\n	\r\0\\_\\%\\') AS `length('\n\t\r\b\0\_\%\\')`,bit_length(_latin1'\n	\r\0\\_\\%\\') AS `bit_length('\n\t\r\b\0\_\%\\')`,bit_length(_latin1'\n	\r\0\\_\\%\\') AS `bit_length('\n\t\r\b\0\_\%\\')`,concat(_latin1'monty',_latin1' was here ',_latin1'again') AS `concat('monty',' was here ','again')`,length(_latin1'hello') AS `length('hello')`,char(ascii(_latin1'h')) AS `char(ascii('h'))`,ord(_latin1'h') AS `ord('h')`,quote((1 / 0)) AS `quote(1/0)`,crc32(_latin1'123') AS `crc32("123")`,replace(_latin1'aaaa',_latin1'a',_latin1'b') AS `replace('aaaa','a','b')`,insert(_latin1'txs',2,1,_latin1'hi') AS `insert('txs',2,1,'hi')`,left(_latin2'a',1) AS `left(_latin2'a',1)`,right(_latin2'a',1) AS `right(_latin2'a',1)`,lcase(_latin2'a') AS `lcase(_latin2'a')`,ucase(_latin2'a') AS `ucase(_latin2'a')`,substr(_latin1'abcdefg',3,2) AS `SUBSTR('abcdefg',3,2)`,substring_index(_latin1'1abcd;2abcd;3abcd;4abcd',_latin1';',2) AS `substring_index("1abcd;2abcd;3abcd;4abcd", ';', 2)`,trim(_latin2' a ') AS `trim(_latin2' a ')`,ltrim(_latin2' a ') AS `ltrim(_latin2' a ')`,rtrim(_latin2' a ') AS `rtrim(_latin2' a ')`,decode(encode(repeat(_latin1'a',100000))) AS `decode(encode(repeat("a",100000),"monty"),"monty")`
SELECT lpad(12345, 5, "#");
lpad(12345, 5, "#")
12345
SELECT conv(71, 10, 36), conv('1Z', 36, 10);
conv(71, 10, 36)	conv('1Z', 36, 10)
1Z	71
SELECT conv(71, 10, 37), conv('1Z', 37, 10), conv(0,1,10),conv(0,0,10), conv(0,-1,10);
conv(71, 10, 37)	conv('1Z', 37, 10)	conv(0,1,10)	conv(0,0,10)	conv(0,-1,10)
NULL	NULL	NULL	NULL	NULL
create table t1 (id int(1), str varchar(10)) DEFAULT CHARSET=utf8;
insert into t1 values (1,'aaaaaaaaaa'), (2,'bbbbbbbbbb');
create table t2 (id int(1), str varchar(10)) DEFAULT CHARSET=utf8;
insert into t2 values (1,'cccccccccc'), (2,'dddddddddd');
select substring(concat(t1.str, t2.str), 1, 15) "name" from t1, t2 
where t2.id=t1.id order by name;
name
aaaaaaaaaaccccc
bbbbbbbbbbddddd
drop table t1, t2;
create table t1 (c1 INT, c2 INT UNSIGNED);
insert into t1 values ('21474836461','21474836461');
Warnings:
Warning	1264	Out of range value adjusted for column 'c1' at row 1
Warning	1264	Out of range value adjusted for column 'c2' at row 1
insert into t1 values ('-21474836461','-21474836461');
Warnings:
Warning	1264	Out of range value adjusted for column 'c1' at row 1
Warning	1264	Out of range value adjusted for column 'c2' at row 1
show warnings;
Level	Code	Message
Warning	1264	Out of range value adjusted for column 'c1' at row 1
Warning	1264	Out of range value adjusted for column 'c2' at row 1
select * from t1;
c1	c2
2147483647	4294967295
-2147483648	0
drop table t1;
select left(1234, 3) + 0;
left(1234, 3) + 0
123
create table t1 (a int not null primary key, b varchar(40), c datetime);
insert into t1 (a,b,c) values (1,'Tom','2004-12-10 12:13:14'),(2,'ball games','2004-12-10 12:13:14'), (3,'Basil','2004-12-10 12:13:14'), (4,'Dean','2004-12-10 12:13:14'),(5,'Ellis','2004-12-10 12:13:14'), (6,'Serg','2004-12-10 12:13:14'), (7,'Sergei','2004-12-10 12:13:14'),(8,'Georg','2004-12-10 12:13:14'),(9,'Salle','2004-12-10 12:13:14'),(10,'Sinisa','2004-12-10 12:13:14');
select count(*) as total, left(c,10) as reg from t1 group by reg order by reg desc limit 0,12;
total	reg
10	2004-12-10
drop table t1;
select trim(null from 'kate') as "must_be_null";
must_be_null
NULL
select trim('xyz' from null) as "must_be_null";
must_be_null
NULL
select trim(leading NULL from 'kate') as "must_be_null";
must_be_null
NULL
select trim(trailing NULL from 'xyz') as "must_be_null";
must_be_null
NULL
CREATE TABLE t1 (
id int(11) NOT NULL auto_increment,
a bigint(20) unsigned default NULL,
PRIMARY KEY  (id)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES
('0','16307858876001849059');
SELECT CONV('e251273eb74a8ee3', 16, 10);
CONV('e251273eb74a8ee3', 16, 10)
16307858876001849059
EXPLAIN 
SELECT id
FROM t1
WHERE a = 16307858876001849059;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	
EXPLAIN 
SELECT id
FROM t1
WHERE a = CONV('e251273eb74a8ee3', 16, 10);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	
DROP TABLE t1;
SELECT CHAR(NULL,121,83,81,'76') as my_column;
my_column
ySQL
SELECT CHAR_LENGTH(CHAR(NULL,121,83,81,'76')) as my_column;
my_column
4
CREATE TABLE t1 (id int PRIMARY KEY, str char(255) NOT NULL);
CREATE TABLE t2 (id int NOT NULL UNIQUE);
INSERT INTO t2 VALUES (1),(2);
INSERT INTO t1 VALUES (1, aes_encrypt('foo', 'bar'));
INSERT INTO t1 VALUES (2, 'not valid');
SELECT t1.id, aes_decrypt(str, 'bar') FROM t1, t2 WHERE t1.id = t2.id;
id	aes_decrypt(str, 'bar')
1	foo
2	NULL
SELECT t1.id, aes_decrypt(str, 'bar') FROM t1, t2 WHERE t1.id = t2.id
ORDER BY t1.id;
id	aes_decrypt(str, 'bar')
1	foo
2	NULL
DROP TABLE t1, t2;
select field(0,NULL,1,0), field("",NULL,"bar",""), field(0.0,NULL,1.0,0.0);
field(0,NULL,1,0)	field("",NULL,"bar","")	field(0.0,NULL,1.0,0.0)
3	3	3
select field(NULL,1,2,NULL), field(NULL,1,2,0);
field(NULL,1,2,NULL)	field(NULL,1,2,0)
0	0
CREATE TABLE t1 (str varchar(20) PRIMARY KEY);
CREATE TABLE t2 (num int primary key);
INSERT INTO t1 VALUES ('notnumber');
INSERT INTO t2 VALUES (0), (1);
SELECT * FROM t1, t2 WHERE num=str;
str	num
notnumber	0
SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6);
str	num
notnumber	0
DROP TABLE t1,t2;
CREATE TABLE t1(
id int(11) NOT NULL auto_increment,
pc int(11) NOT NULL default '0',
title varchar(20) default NULL,
PRIMARY KEY (id)
);
INSERT INTO t1 VALUES
(1, 0, 'Main'),
(2, 1, 'Toys'),
(3, 1, 'Games');
SELECT t1.id, CONCAT_WS('->', t3.title, t2.title, t1.title) as col1
FROM t1 LEFT JOIN t1 AS t2 ON t1.pc=t2.id
LEFT JOIN t1 AS t3 ON t2.pc=t3.id;
id	col1
1	Main
2	Main->Toys
3	Main->Games
SELECT t1.id, CONCAT_WS('->', t3.title, t2.title, t1.title) as col1
FROM t1 LEFT JOIN t1 AS t2 ON t1.pc=t2.id
LEFT JOIN t1 AS t3 ON t2.pc=t3.id
WHERE CONCAT_WS('->', t3.title, t2.title, t1.title) LIKE '%Toys%';
id	col1
2	Main->Toys
DROP TABLE t1;
CREATE TABLE t1(
trackid     int(10) unsigned NOT NULL auto_increment,
trackname   varchar(100) NOT NULL default '',
PRIMARY KEY (trackid)
);
CREATE TABLE t2(
artistid    int(10) unsigned NOT NULL auto_increment,
artistname  varchar(100) NOT NULL default '',
PRIMARY KEY (artistid)
);
CREATE TABLE t3(
trackid     int(10) unsigned NOT NULL,
artistid    int(10) unsigned NOT NULL,
PRIMARY KEY (trackid,artistid)
);
INSERT INTO t1 VALUES (1, 'April In Paris'), (2, 'Autumn In New York');
INSERT INTO t2 VALUES (1, 'Vernon Duke');
INSERT INTO t3 VALUES (1,1);
SELECT CONCAT_WS(' ', trackname, artistname) trackname, artistname
FROM t1 LEFT JOIN t3 ON t1.trackid=t3.trackid
LEFT JOIN t2 ON t2.artistid=t3.artistid
WHERE CONCAT_WS(' ', trackname, artistname) LIKE '%In%';
trackname	artistname
April In Paris Vernon Duke	Vernon Duke
Autumn In New York	NULL
DROP TABLE t1,t2,t3;
create table t1 (b varchar(5));
insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');
select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;
b	substring(b,1)	substring(b,-1)	substring(b,-2)	substring(b,-3)	substring(b,-4)	substring(b,-5)
ab	ab	b	ab			
abc	abc	c	bc	abc		
abcd	abcd	d	cd	bcd	abcd	
abcde	abcde	e	de	cde	bcde	abcde
select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;
b	substring(b,1)	substring(b,-1)	substring(b,-2)	substring(b,-3)	substring(b,-4)	substring(b,-5)
ab	ab	b	ab			
abc	abc	c	bc	abc		
abcd	abcd	d	cd	bcd	abcd	
abcde	abcde	e	de	cde	bcde	abcde
drop table t1;
select hex(29223372036854775809), hex(-29223372036854775809);
hex(29223372036854775809)	hex(-29223372036854775809)
FFFFFFFFFFFFFFFF	FFFFFFFFFFFFFFFF
create table t1 (i int);
insert into t1 values (1000000000),(1);
select lpad(i, 7, ' ') as t from t1;
Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
def					t	253	7	7	Y	128	31	63
t
1000000
      1
select rpad(i, 7, ' ') as t from t1;
Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
def					t	253	7	7	Y	128	31	63
t
1000000
1      
drop table t1;
create table t1 (d decimal default null);
insert into t1 values (null);
select format(d, 2) from t1;
format(d, 2)
NULL
drop table t1;
create table t1 (c varchar(40));
insert into t1 values ('y,abc'),('y,abc');
select c, substring_index(lcase(c), @q:=',', -1) as res from t1;
c	res
y,abc	abc
y,abc	abc
drop table t1;