修改mysql字符集

(1) 最简单的修改方法，就是修改mysql的my.ini文件中的字符集键值，

如 character_set_server=utf8

修改完后，重启mysql的服务，service mysql restart

使用 mysql> SHOW VARIABLES LIKE 'character%';查看，发现数据库编码均已改成utf8

+--------------------------+---------------------------------+
| Variable_name | Value |
+--------------------------+---------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | D:"mysql-5.0.37"share"charsets" |
+--------------------------+---------------------------------+
(2) 还有一种修改mysql默认字符集的方法，就是使用mysql的命令

mysql> SET character_set_client = utf8 ;
mysql> SET character_set_connection = utf8 ;
mysql> SET character_set_database = utf8 ;
mysql> SET character_set_results = utf8 ;
mysql> SET character_set_server = utf8 ;

mysql> SET collation_connection = utf8 ;
mysql> SET collation_database = utf8 ;
mysql> SET collation_server = utf8 ;
一般就算设置了表的mysql默认字符集为utf8并且通过UTF-8编码发送查询，你会发现存入数据库的仍然是乱码。问题就出在这个connection连接层上。解决方法是在发送查询前执行一下下面这句：

SET NAMES 'utf8';
它相当于下面的三句指令：

SET character_set_client = utf8;
SET character_set_results = utf8;
SET character_set_connection = utf8;

修改表级
mysql>ALTER TABLE table_name DEFAULT CHARSET utf8; 更改了后永久生效

3.4修改列级修改示例
mysql>ALTER TABLE products CHANGE products_model VARCHAR( 20 ) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL; 更改了后永久生效

3.5更改连接字符集
a. 临时更改：mysql> SET GLOBAL character_set_client utf8;

b. 永久更改：打开/etc/mysql/my.cnf,在[client]后添加character_set_server=utf8

一、避免创建数据库及表出现中文乱码和查看编码方法
1、创建数据库的时候：

CREATE DATABASE test
CHARACTER SET 'utf8'
COLLATE 'utf8_general_ci';
2、建表的时候

CREATE TABLE database_user (
ID varchar(40) NOT NULL default '',
UserID varchar(40) NOT NULL default '',
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

设置数据库db_name默认为utf8:

[sql] view plain copy
ALTER DATABASE db_name DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
设置表tb_name默认编码为utf8:
[sql] view plain copy
ALTER TABLE tb_name DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;