Windows/Linux下MySql 不区分大小写设置有关问题

Windows/Linux下MySql 不区分大小写设置问题

MySQL在Linux下数据库名、表名、列名、别名大小写规则:

 

1、数据库名与表名是严格区分大小写
2、表的别名是严格区分大小写
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

 

注意:

 

A、Linux下MySQL安装完后默认:区分表名的大小写,不区分列名的大小写

 

B、改变表名的大小写区分规则的方法:用root帐号登录,在/etc/my.cnf 或 /etc/mysql/my.cnf 中的[mysqld]后添加添加lower_case_table_names=1,重启MySQL服务,若设置成功,则不再区分表名的大小写。   http://blog.rekfan.com/?p=191

 

MYSQL在默认的情况下查询是不区分大小写的,例如:

 

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:
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:

 

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:

 

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

 


 

[mysqld]
lower_case_table_names=1
#(0:区分;1:不区分)

然后重启MYSQL服务。

 


 

mysql> show variables like '%case_table%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| lower_case_table_names | 1 |
+------------------------+-------+

 

1 row in set (0.00 sec)