On Windows
If you are using Windows Open the Command Prompt and type
To Stop MySQL Service:
net stop MySQL80
To Start MySQL Service:
net start MySQL80
On Linux
# /etc/init.d/mysqld start
# /etc/init.d/mysqld stop
# /etc/init.d/mysqld restart
Fedora / Red Hat also support this:
# service mysqld start
# service mysqld stop
# service mysqld restart
Also Systemd based distrubutions (like Ubuntu or Arch Linux) support this:
# systemctl start mysql
# systemctl stop mysql
# systemctl restart mysql
I know this answer is late but i hope it helps for some one.