MySQL中文字符乱码解决

一、先查看数据库字符集

 mysql> show variables like '%char%';
 +--------------------------+----------------------------+
 | 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 | /usr/share/mysql/charsets/ |
 +--------------------------+----------------------------+
 8 rows in set (0.00 sec)

mysql> show variables like '%collation%';
 +----------------------+-----------------+
 | Variable_name | Value |
 +----------------------+-----------------+
 | collation_connection | utf8_general_ci |
 | collation_database | utf8_general_ci |
 | collation_server | utf8_general_ci |
 +----------------------+-----------------+
 3 rows in set (0.00 sec)

二、查看 MySQL 数据表（table ） 的字符集。

mysql> show table status from pubs like '%students%';

三、查看 MySQL 数据列（column ）的字符集。

mysql> show full columns from students;

四、查看当前安装的 MySQL 所支持的字符集。

mysql> show charset;
+----------+-----------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+-----------------------------+---------------------+--------+
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| binary | Binary pseudo charset | binary | 1 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
+----------+-----------------------------+---------------------+--------+
39 rows in set (0.00 sec)

sudo vi /etc/mysql/my.cnf
在以下地方加入：

[mysqld]

character-set-server=utf8

init_connect=’SET NAMES utf8′     #（设定连接 mysql数据库时使用utf8编码，以让 mysql数据库为utf8 运行）
[mysql]

default-character-set=utf8

*有说在[mysqld] 处添加default-character-set=utf8，但设了后重启不了服务
重启 MySQL
sudo /etc/init.d/mysql restart 
#或者 
sudo service mysql restart
其他的一些设置方法：
修改数据库的字符集
mysql>use mydb
mysql>alter database mydb character set utf-8;
创建数据库指定数据库的字符集
mysql>create database mydb character set utf-8;
通过配置文件修改 :

修改/var/lib/mysql/mydb/db.opt
default-character-set=latin1
default-collation=latin1_swedish_ci
为
default-character-set=utf8
default-collation=utf8_general_ci
一般就算设置了表的默认字符集为 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;
//修改数据库
mysql> alter database name character set utf8;
//修改表
alter table 表名 convert to character set utf8;
#或者
mysql>alter table 表名 default character set utf8;
//修改字段
alter table 表名 modify column 字段名 varchar(30) character set utf8 not null;
//添加表字段
alter table 表名 add column 字段名 varchar (20) character set utf8;
例：
mysql> alter table students character set utf8;
mysql> alter table students modify column name varchar(10) character set utf8;