卸载老版本MySQL
find / -name mysql
rm -rf 上边查找到的路径，多个路径用空格隔开
#或者下边一条命令即可 find / -name mysql|xargs rm -rf
或者
rpm -qa | grep -i mysql
卸载
rpm -ev mysql-libs-5.1.73-7.el6.x86_64
如果有依赖
rpm -ev mysql-libs-5.1.73-7.el6.x86_64 --nodeps
还失败，尝试以下命令
rpm -e --noscripts mysql-libs-5.1.73-7.el6.x86_64
1、解压文件：
tar -zxvf mysql-5.6.31-linux-glibc2.5-x86_64.tar.gz
2、删除安装包，重命名解压后的文件
rm -f mysql-5.6.31-linux-glibc2.5-x86_64.tar.gz mv mysql-5.6.31-linux-glibc2.5-x86_64/ mysql
或者复制
cp -r mysql-5.6.27-linux-glibc2.5-x86_64 /usr/local/mysql
3、添加mysql用户组和mysql用户
先检查是否有mysql用户组和mysql用户
groups mysql
若无，则添加；
groupadd mysql
useradd -r -g mysql mysql
4、进入mysql目录更改权限
[root@tyz~]# cd /usr/local/mysql/
[root@tyz mysql]# chown -R mysql:mysql ./
5、执行安装脚本
--------------------------------使用默认即可，不需要修改------------------------------------
修改/etc/my.cnf
[root@tyz mysql]# vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
修改
[root@tyz mysql]# vim /etc/my.cnf
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
[mysqld_safe]
log-error=/usr/local/mysql/data/mysqld.log
pid-file=/usr/local/mysql/data/mysqld.pid
------------------------------------------不需要修改-------------------------------
可能会出现乱码，进行如下修改
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html
[mysqld]
port=3306
character_set_server=utf8
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
# These are commonly set, remove the # and set as required.
# basedir = .....
# datadir = .....
# port = .....
# server_id = .....
# socket = .....
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
[client]
port=3306
default-character-set=utf8
[root@tyz mysql]# ./scripts/mysql_install_db --user=mysql
安装完之后修改当前目录拥有者为root用户，修改data目录拥有者为mysql
chown -R root:root ./
chown -R mysql:mysql data
6、更改mysql密码
启动，如果已启动，使用kill杀掉进程
./support-files/mysql.server start
[root@jt-mtg-db mysql]# ./support-files/mysql.server start
Starting MySQL. ERROR! The server quit without updating PID file (/var/lib/mysql/jt-mtg-db.pid).
出现以上错误，
MySQL启动之后再执行如下命令更改密码：
[root@tyz mysql]# ./bin/mysqladmin -u root -h localhost.localdomain password '123456'
[root@tyz mysql]#./bin/mysql -h127.0.0.1 -uroot –p123456
登录之后，将其他用户的密码也改为123456
mysql> update mysql.user set password=password('123456') where user='root';
mysql> flush privileges;
7、增加远程登录权限
mysql> grant all privileges on *.* to root@'%' identified by '123456';
mysql> flush privileges;
8、将MySQL加入Service系统服务
复制
[root@tyz mysql]# cp support-files/mysql.server /etc/init.d/mysqld
[root@tyz mysql]# chkconfig --add mysqld
[root@tyz mysql]# chkconfig mysqld on
//查看是否成功
[root@tyz mysql]# chkconfig --list mysqld
mysqld 0:关闭 1:关闭 2:启用 3:启用 4:启用 5:启用 6:关闭
//如果看到mysql的服务，并且3,4,5都是on的话则成功，如果是off，则键入
service mysqld restart
service mysqld status
验证
重启，执行以下命令验证
netstat -na | grep 3306