https://www.linuxidc.com/Linux/2017-05/143864.htm
进入：mysql -u root -p
Ubuntu18安装5.7
Ubuntu18.04安装mysql5.7
1.1安装
首先执行下面三条命令：
# 安装mysql服务
sudo apt-get install mysql-server
# 安装客户端
sudo apt install mysql-client
# 安装依赖
sudo apt install libmysqlclient-dev
# 检查状态
sudo netstat -tap | grep mysql
1.2设置root密码
mysql5.7安装完成后普通用户不能进mysql，原因：root的plugin被修改成了auth_socket，用密码登陆的plugin应该是mysql_native_password，直接用root权限登录就不用密码,修改root密码和登录验证方式：
$ sudo su
# mysql
mysql>
mysql> select user, plugin from mysql.user;
+------------------+-----------------------+
| user | plugin |
+------------------+-----------------------+
| root | auth_socket |
| mysql.session | mysql_native_password |
| mysql.sys | mysql_native_password |
| debian-sys-maint | mysql_native_password |
+------------------+-----------------------+
4 rows in set (0.00 sec)
mysql> update mysql.user set authentication_string=PASSWORD('123456'), plugin='mysql_native_password' where user='root';
mysql> flush privileges;
mysql> exit
Bye
# exit
$ sudo /etc/init.d/mysql restart
$ mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.22-0ubuntu18.04.1 (Ubuntu)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
1.3配置mysql远程登录
# 修改配置文件，注释掉bind-address = 127.0.0.1
$ sudo vi /etc/mysql/mysql.conf.d/mysqld.cnf
# 保存退出，然后进入mysql服务，执行授权命令：
$ mysql -uroot -p
mysql> grant all on *.* to root@'%' identified by '123456' with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> exit
Bye
$ sudo /etc/init.d/mysql restart
