Explain how to completely delete mysql from Centos

1. MySQL installed in yum mode

$ yum remove mysql mysql-server mysql-libs compat-mysql51
$ rm -rf /var/lib/mysq
$ rm /etc/my.cnf

Check if mysql software is available:

$ rpm -qa|grep mysql

If it exists, continue to delete it. Delete mode: yum remove + [name].

2. mysql installed by rpm

a) to see if mysql is installed in the rpm package in the system:

[root@localhost opt]# rpm -qa | grep -i mysql
MySQL-server-5.6.17-1.el6.i686
MySQL-client-5.6.17-1.el6.i686

Uninstall mysql b)

[root@localhost local]# rpm -e MySQL-server-5.6.17-1.el6.i686
[root@localhost local]# rpm -e MySQL-client-5.6.17-1.el6.i686

c) delete the mysql service

[root@localhost local]# chkconfig --list | grep -i mysql
[root@localhost local]# chkconfig --del mysql

d) delete the scattered mysql folder

[root@localhost local]# whereis mysql # or 
find / -name mysql

mysql: /usr/lib/mysql /usr/share/mysql

Empty all directories and files associated with mysql

rm -rf /usr/lib/mysql
rm -rf /usr/share/mysql
rm -rf /usr/my.cnf

After the above steps, the mysql should have been completely uninstalled.