Firstly, you need to remove the current MySQL if you are already using:

$ sudo apt-get purge mysql-client-core-5.5

Now, to install MySQL, by running the following commands in terminal:

$ sudo apt-get install mysql-server
$ sudo apt-get install mysql-client

During the installation you will be asked to enter a password for the MySQL root user.

Use any password you like and remember it.

For Mysql-Workbench(optional):

sudo apt-get install mysql-workbench

First you have to remove mysql completely from your system using following commands in terminal

sudo apt-get remove --purge mysql-server mysql-client mysql-common

sudo apt-get update && sudo apt-get upgrade

sudo apt-get autoremove

sudo apt-get autoclean

Now try to reinstall Mysql.

To open mysql command line:

sudo mysql -u root -p password

View all existing databases:

show databases;

If you want to use an existing database:

use DATABASE_NAME;

Or, create a database by following command:

create database db_name

If you wish to view all tables use command:

show tables;

If you want to IMPORT an existing database with .sql file, use the following command:

Note: Before imposting you need to use a database into which you need to import your dump.

mysql> \. home/db_dump.sql;