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1、linux下mysql安装完后是默认:区分表名的大小写,不区分列名的大小写;
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2、用root帐号登录后,在/etc/my.cnf 中的[mysqld]后添加添加lower_case_table_names=1,重启MYSQL服务,这时已设置成功:不区分表名的大小写;
lower_case_table_names参数详解:
lower_case_table_names = 0
其中 0:区分大小写,1:不区分大小写
MySQL在Linux下数据库名、表名、列名、别名大小写规则是这样的:
1、数据库名与表名是严格区分大小写的;
2、表的别名是严格区分大小写的;
3、列名与列的别名在所有的情况下均是忽略大小写的;
4、变量名也是严格区分大小写的;
MySQL在Windows下都不区分大小写。
3、如果想在查询时区分字段值的大小写,则:字段值需要设置BINARY属性,设置的方法有多种:
A、创建时设置:
CREATE TABLE T(
A VARCHAR(10) BINARY
);
B、使用alter修改:
ALTER TABLE `tablename` MODIFY COLUMN `cloname` VARCHAR(45) BINARY;
C、mysql table editor中直接勾选BINARY项。
show Variables like 'lower_case_table%'查看lower_case_table_names的值:
0代表区分,1代表不区分。
mysql show Variables like 'lower_case_table%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| lower_case_table_names | 0 |
+------------------------+-------+
1 row in set (0.01 sec)
mysql
select * from abc whre id="a" 与
select * from abc whre id="A" 查询出的结果是不同的
对单个字段设置的方式就不用说了,希望得到是对mysql默认的设置或是对整个库的设置
是否区分大小写和校对规则有关,默认设的规则是大小写不敏感的。
show create table如果看到collate是ci结尾,那么就是不区别的,如果cs或bin结尾,就是区别的。
如果建表的时候选择的是区别大小写的规则而查询的时候又暂时不想区别,
可以用类似
WHERE column_name COLLATE latin1_general_ci = 'xxx'
的写法改变查询使用的校对规则
1、linux下mysql安装完后是默认:区分表名的大小写,不区分列名的大小写; 2、用root帐号登录后,在/etc/my.cnf 中的[mysqld]后添加添加lower_case_table_names=1,重启MYSQL服务,这时已设置成功:不区分表名的大小写; lower_case_table_names...
1、一种方法是可以设置表或行的collation,使其为binary或case
sensitive。在MySQL中,对于Column
Collate其约定的命名方法如下:
*_bin:
表示的是binary
case
sensitive
collation,也就是说是区分大小写的
*_cs:
case
sensitive
collation,区分大小写
*_ci:
case
insensitive
collation,不区分大小写
###########
#
Start
binary
collation
example
###########
mysql
create
table
case_bin_test
(word
VARCHAR(10))
CHARACTER
SET
latin1
COLLATE
latin1_bin;
Query
OK,
rows
affected
(0.02
sec)
mysql
INSERT
INTO
case_bin_test
VALUES
('Frank'),('Google'),('froogle'),('flickr'),('FlicKr');
Query
OK,
5
rows
affected
(0.00
sec)
Records:
5
Duplicates:
Warnings:
mysql
SELECT
*
FROM
case_bin_test
WHERE
word
LIKE
'f%';
+---------+
|
word
|
+---------+
|
froogle
|
|
flickr
|
+---------+
2
rows
in
set
(0.00
sec)
mysql
SELECT
*
FROM
case_bin_test
WHERE
word
LIKE
'F%';
+---------+
|
word
|
+---------+
|
Frank
|
|
FlicKr
|
+---------+
4
rows
in
set
(0.00
sec)
###########
#
End
###########
2、另外一种方法
###########
#
Start
case
sensitive
collation
example
###########
mysql
create
table
case_cs_test
(word
VARCHAR(10))
CHARACTER
SET
latin1
COLLATE
latin1_general_cs;
Query
OK,
rows
affected
(0.08
sec)
mysql
INSERT
INTO
case_cs_test
VALUES
('Frank'),('Google'),('froogle'),('flickr'),('FlicKr');
Query
OK,
5
rows
affected
(0.00
sec)
Records:
5
Duplicates:
Warnings:
mysql
SELECT
*
FROM
case_cs_test
WHERE
word
LIKE
'F%';
+---------+
|
word
|
+---------+
|
Frank
|
|
FlicKr
|
+---------+
4
rows
in
set
(0.00
sec)
mysql
SELECT
*
FROM
case_cs_test
WHERE
word
LIKE
'f%';
+---------+
|
word
|
+---------+
|
froogle
|
|
flickr
|
+---------+
2
rows
in
set
(0.00
sec)
###########
#
end
###########
3、还有一种方法就是在查询时指定collation
mysql
create
table
case_test
(word
VARCHAR(10))
CHARACTER
SET
latin1;
Query
OK,
rows
affected
(0.01
sec)
mysql
INSERT
INTO
case_test
VALUES
('Frank'),('Google'),('froogle'),('flickr'),('FlicKr');
Query
OK,
7
rows
affected
(0.01
sec)
Records:
7
Duplicates:
Warnings:
mysql
SELECT
*
FROM
case_test
WHERE
word
LIKE
'f%';
+---------+
|
word
|
+---------+
|
Frank
|
|
froogle
|
|
flickr
|
|
FlicKr
|
+---------+
6
rows
in
set
(0.01
sec)
mysql
SELECT
*
FROM
case_test
WHERE
word
LIKE
'F%';
+---------+
|
word
|
+---------+
|
Frank
|
|
froogle
|
|
flickr
|
|
FlicKr
|
+---------+
6
rows
in
set
(0.01
sec)
mysql
SELECT
*
FROM
case_test
WHERE
word
COLLATE
latin1_bin
LIKE
'F%';
+---------+
|
word
|
+---------+
|
Frank
|
|
FlicKr
|
+---------+
4
rows
in
set
(0.05
sec)
mysql
SELECT
*
FROM
case_test
WHERE
word
COLLATE
latin1_bin
LIKE
'f%';
+---------+
|
word
|
+---------+
|
froogle
|
|
flickr
|
+---------+
2
rows
in
set
(0.00
sec)
mysql
SELECT
*
FROM
case_test
WHERE
word
LIKE
'f%'
COLLATE
latin1_bin;
+---------+
|
word
|
+---------+
|
froogle
|
|
flickr
|
+---------+
2
rows
in
set
(0.00
sec)
mysql
SELECT
*
FROM
case_test
WHERE
word
LIKE
'F%'
COLLATE
latin1_bin;
+---------+
|
word
|
+---------+
|
Frank
|
|
FlicKr
|
+---------+
4
rows
in
set
(0.01
sec)
mysql
SELECT
*
FROM
case_test
WHERE
word
LIKE
'F%'
COLLATE
latin1_general_cs;
+---------+
|
word
|
+---------+
|
Frank
|
|
FlicKr
|
+---------+
4
rows
in
set
(0.04
sec)