Installing,Starting Service & Setting root password of My Sql

First set Yum repository of MySQL

then install it by using following command

yum -y install mysql-server mysql 
or
yum -y install mysql* 

Starting MySQL Server:-

Execute Following Command:-
chkconfig mysqld on
/etc/init.d/mysqld start or service mysqld restart

Setting Up root Password:-
mysqladmin -u root password NEWPASSWORD

Testing MySQL Connectivity 

mysql -u root -p.

Enjoy