#命令1
sudo apt-get update
#命令2
sudo apt-get install mysql-server

sudo mysql_secure_installation

weison@ubuntu19-04:~$ sudo mysql_secure_installation

Securing the MySQL server deployment.

Connecting to MySQL using a blank password.

VALIDATE PASSWORD PLUGIN can be used to test passwords
and improve security. It checks the strength of password
and allows the users to set only those passwords which are
secure enough. Would you like to setup VALIDATE PASSWORD plugin?

Press y|Y for Yes, any other key for No: N（选择N，不会进行密码的强校验）
Please set the password for root here.

New password: 

Re-enter new password: 
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

Remove anonymous users? (Press y|Y for Yes, any other key for No) : N（选择N，不删除匿名用户）

 ... skipping.


Normally, root should only be allowed to connect from
‘localhost‘. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : N（选择N，允许root远程连接）

 ... skipping.
By default, MySQL comes with a database named ‘test‘ that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.


Remove test database and access to it? (Press y|Y for Yes, any other key for No) : N（选择N，不删除test数据库）

 ... skipping.
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : Y（选择Y，修改权限立即生效）
Success.

All done! 

# 登陆mysql
sudo mysql -uroot -p
#切换数据库
use mysql;
#查询用户表命令：
select User,authentication_string,Host from user;

#设置权限与密码
GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘%‘ IDENTIFIED BY ‘root‘;  
#刷新cache中配置
flush privileges;  

##1 创建数据库studentService
CREATE DATABASE studentService;
##2 创建用户teacher(密码admin) 并赋予其studentService数据库的远程连接权限
GRANT ALL PRIVILEGES ON teacher.* TO studentService@% IDENTIFIED BY "admin";

mysql -uroot -p;

use mysql;

user set password=PASSWORD(‘新密码‘) where user=‘root‘;

FLUSH PRIVILEGES;

use mysql;

update user set authentication_string=PASSWORD(‘123456‘) where user=‘root‘;

FLUSH PRIVILEGES;

systemctl status mysql.service
或
sudo service mysql status

weison@ubuntu19-04:~$ systemctl status mysql.service
● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
   Active: active (running) since Sat 2019-06-29 11:10:10 CST; 15min ago
 Main PID: 8545 (mysqld)
    Tasks: 28 (limit: 4915)
   Memory: 173.4M
   CGroup: /system.slice/mysql.service
           └─8545 /usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid

6月 29 11:10:10 ubuntu19-04 systemd[1]: Starting MySQL Community Server...
6月 29 11:10:10 ubuntu19-04 systemd[1]: Started MySQL Community Server.

#停止
sudo service mysql stop
#启动
sudo service mysql start