如果是apt-get安装的
sudo apt-get --purge remove mysql-server
sudo apt-get --purge remove mysql-client
sudo apt-get --purge remove mysql-common
apt-get -f autoremove
apt-get autoclean
rm /etc/mysql/ -R
rm /var/lib/mysql/ -R
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copy到/opt/mysql目录下
groupadd mysql
useradd -g mysql mysql
chown -R mysql .
chgrp -R mysql .
scripts/mysql_install_db --user=mysql (此步骤之前请确认/etc下没有 my.cnf和 mysql/my.cnf)
chown -R root .
chown -R mysql data
cp support-files/my-small.cnf /etc/my.cnf
cp support-files/mysql.server /etc/init.d/mysqld
在my.cnf 加上basedir=/opt/mysql/
chmod +x /etc/init.d/mysqld
/etc/init.d/mysqld start
Debian MySQL 卸载和安装
原文：http://www.cnblogs.com/healerkx/p/4206788.html
