MYSQL在默认的情况下查询是不区分大小写的，例如：
|
1
2
3
4
5
6
7
|
mysql> create table t1( -> name varchar(10)); Query OK, 0 rows affected (0.09 sec) mysql> insert into t1 values('you'),('You'),('YOU'); Query OK, 3 rows affected (0.05 sec) Records: 3 Duplicates: 0 Warnings: 0 |
对这个表，缺省情况下，下面两个查询的结果是一样的：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
|
mysql> select * from t1 where name = 'you'; +------+ | name | +------+ | you | | You | | YOU | +------+ 3 rows in set (0.00 sec) mysql> select * from t1 where name = 'YOU'; +------+ | name | +------+ | you | | You | | YOU | +------+ 3 rows in set (0.00 sec) |
如果想让MYSQL知道你输入的字母是大写还是小写的，修改表：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
|
mysql> alter table t1 change name name varchar(10) binary; Query OK, 3 rows affected (0.20 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select * from t1 where name = 'you'; +------+ | name | +------+ | you | +------+ 1 row in set (0.00 sec) mysql> select * from t1 where name = 'YOU'; +------+ | name | +------+ | YOU | +------+ 1 row in set (0.00 sec) |
如果你只是想在SQL语句中实现的话：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
|
mysql> select * from t1 where name = binary 'YOU'; +------+ | name | +------+ | YOU | +------+ 1 row in set (0.02 sec) mysql> select * from t1 where name = binary 'you'; +------+ | name | +------+ | you | +------+ 1 row in set (0.00 sec) |
如果不想这么麻烦而想服务一开启就让大小写一致的话：
可以修改my.ini或者my.cnf
|
1
2
3
|
[mysqld] lower_case_table_names=1 （0：区分；1：不区分） |
然后重启MYSQL服务。
|
1
2
3
4
5
6
7
|
mysql> show variables like '%case_table%'; +------------------------+-------+ | Variable_name | Value | +------------------------+-------+ | lower_case_table_names | 1 | +------------------------+-------+ 1 row in set (0.00 sec)在跨平台的程序设计中要注意到mysql的一些系统变量在windows和linux上的缺省值是不同的, 比如mysql表名称的大小写变量. 在windows上lower_case_table_names变量的缺省值为1; 在linux上为0; 在mac os上为2; 该变量值的详细定义如下
|