How to stop and start the mysql?

If Mysql is running as a service:

sudo service mysql restart;

or

sudo service path/to/mysql restart;

Edit:

check if mysql is running

service --status-all
service --status-all | grep mysql

If Mysql is running, use

To Restart: service mysqld restart

Other command which can be used if necessary are given below.

To Stop: service mysqld stop

To Start: service mysqld start

to stop mysql account is:

sudo mysqladmin -h localhost -u root -p shutdown

to start is:
sudo systemctl start mysql.service

to confirm:

sudo mysql -h localhost -u root -p

NB:
the default password for root account is root

**not sure but i think this closes connection for all accounts & also starts for all accounts though you have stop using an account with privilege access/root access by using the grant statement.

example

GRANT ALL PRIVILEGES ON databasename.* TO 'username'@'localhost';

source http://www.luciopanasci.it/Ebooks/MySQL%20Cookbook,%203rd%20Edition.pdf
page 2 topic 1.1**

Usually you do

/etc/init.d/mysql start/stop/restart

It may be called mysqld or mysql-server or something like that. If you’re on Ubuntu, you have to do

service mysql start/stop/restart

there it may be mysqld or mysql-server or something like this as well.

As root, run
service mysqld restart

If that does not work, try
/etc/init.d/mysqld restart

Instead of restart you can use :

start to start mysql

stop to stop it