删除已经安装的mysql（此方法可以保证删除干净）
1.1 查看mysql的安装路径：
[root@bogon ~]# whereis mysql
mysql: /usr/bin/mysql /usr/lib/mysql /usr/share/mysql /usr/share/man/man1/mysql.1.gz
然后分别用 rm -rf 删除指定路径
1.2 查看mysql的安装包：
[root@bogon ~]# rpm -qa|grep mysql
mysql-community-client-5.6.26-2.el6.i686
mysql-community-release-el6-5.noarch
mysql-community-common-5.6.26-2.el6.i686
mysql-community-libs-5.6.26-2.el6.i686
mysql-community-server-5.6.26-2.el6.i686
[root@bogon ~]#
1.3 卸载mysql
[root@bogon ~]# yum remove mysql
删除mysql的数据库文件:删除/var/llib/mysql目录
=================================================================================================
1.4安装mysql
1、命令安装mysql
# yum install mysql mysql-server mysql-devel -y
2、设置mysqld随机启动，执行下面命令进行设置
# chkconfig mysqld on
3、启动mysqld服务
# service mysqld start
4、给root用户设置密码
# /usr/bin/mysqladmin -u root password 'root'
5、远程连接授权
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'root' WITH GRANT OPTION;