修改MySQL字符编码【Linux】

环境：CentOS + MySQL5.5.25a

1. 首先登陆MySQL查看默认编码，应该存在Latin编码，不支持中文

mysql> show variables like '%character%';

2. 关闭MySQL

# /etc/init.d/mysql stop

3. 接下来创建并修改配置文件

把/usr/share/doc/mysql-server-5.1.52/my-large.cnf 复制到 /etc/my.cnf

用命令：cp /usr/share/doc/mysql-server-5.1.52/my-large.cnf  /etc/my.cnf

打开my.cnf后添加配置信息

在[client]节点下面加入　　default-character-set=utf8
在[mysqld]节点下面加　　character_set_server=utf8　　　init_connect='SET NAMES utf8'
在[mysql]节点下面加入　default-character-set=utf8

修改后的配置文件my.cnf如下：

# Example MySQL config file for large systems.
#
# This is for a large system with memory = 512M where the system runs mainly
# MySQL.
#
# MySQL programs look for option files in a set of
# locations which depend on the deployment platform.
# You can copy this option file to one of those
# locations. For information about these locations, see:
# http://dev.mysql.com/doc/mysql/en/option-files.html
#
# In this file, you can use all long options that a program supports.
# If you want to know which options a program supports, run the program
# with the "--help" option.

# The following options will be passed to all MySQL clients
[client]
#password	= your_password
port		= 3306
socket		= /var/lib/mysql/mysql.sock
default-character-set=utf8
# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port		= 3306
socket		= /var/lib/mysql/mysql.sock
skip-external-locking
key_buffer_size = 256M
max_allowed_packet = 1M
table_open_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size= 16M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 8
character_set_server=utf8
init_connect='SET NAMES utf8'

# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!
# 
#skip-networking

# Replication Master Server (default)
# binary logging is required for replication
log-bin=mysql-bin

# binary logging format - mixed recommended
binlog_format=mixed

# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
server-id	= 1

# Replication Slave (comment out master section to use this)
#
# To configure this host as a replication slave, you can choose between
# two methods :
#
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
#    the syntax is:
#
#    CHANGE MASTER TO MASTER_HOST=, MASTER_PORT=,
#    MASTER_USER=, MASTER_PASSWORD= ;
#
#    where you replace , ,  by quoted strings and
#     by the master's port number (3306 by default).
#
#    Example:
#
#    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,
#    MASTER_USER='joe', MASTER_PASSWORD='secret';
#
# OR
#
# 2) Set the variables below. However, in case you choose this method, then
#    start replication for the first time (even unsuccessfully, for example
#    if you mistyped the password in master-password and the slave fails to
#    connect), the slave will create a master.info file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the master.info file, unless you shutdown
#    the slave server, delete master.info and restart the slaver server.
#    For that reason, you may want to leave the lines below untouched
#    (commented) and instead use CHANGE MASTER TO (see above)
#
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
#server-id       = 2
#
# The replication master for this slave - required
#master-host     =   
#
# The username the slave will use for authentication when connecting
# to the master - required
#master-user     =   
#
# The password the slave will authenticate with when connecting to
# the master - required
#master-password =   
#
# The port the master is listening on.
# optional - defaults to 3306
#master-port     =  
#
# binary logging - not required for slaves, but recommended
#log-bin=mysql-bin

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /var/lib/mysql
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /var/lib/mysql
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 256M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 64M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
default-character-set=utf8
[myisamchk]
key_buffer_size = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

4. 启动MySQL

# /etc/init.d/mysql start

5. 再次查看编码

mysql> show variables like '%character%';

注：即使做了以上修改如果直接数据库再创建表，然后存入中文，取出来的还会是问号。

解决的办法是：创建数据库的时候指明默认字符集为utf8，如：
　　create database test default character set utf8;