Install and Setup MySQl

*** Install mysql ***
$ sudo apt update
$ sudo apt install mysql-server
Do Secire Setup
$ sudo mysql_secure_installation
See Service Status
$ sudo systemctl status mysql.service

*** Set password of root ***
See Debian User Infomation
$ sudo cat /etc/mysql/debian.cnf
Find Lines
---------------------------
user     = debian-sys-maint
password = Sg4WZAbDRPIMrA6C
---------------------------
Login 
$ sudo mysql -u debian-sys-maint -p
Emter password:Sg4WZAbDRPIMrA6C
(change root password as newpassword)
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'mewpassword'
mysql> quit
$ sudo mysql -u root -p