声明：全文均摘抄于MySQL ERROR 1698 (28000) 错误
//错误起源：~$ mysql -u root -pEnter password: ERROR 1698 (28000): Access denied for user 'root'@'localhost'
解决步骤：
停止mysql服务~$ sudo service mysql stop
以安全模式启动MySQL
~$ sudo mysqld_safe --skip-grant-tables &
MySQL启动之后就可以不用密码登陆了
~$ mysql -u rootWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 2Server version: 5.7.10 MySQL Community Server (GPL)
查看一下user表，错误的起因就是在这里， root的plugin被修改成了auth_socket，用密码登陆的plugin应该是mysql_native_password。
mysql> select user, plugin from mysql.user;+-----------+-----------------------+| user| plugin|+-----------+-----------------------+| root| auth_socket || mysql.sys | mysql_native_password || dev | mysql_native_password |+-----------+-----------------------+3 rows in set (0.01 sec)
关于auth_socket，在官方有说明：/doc/mysql-security-excerpt/5.5/en/socket-authentication-plugin.html，反正现在暂时不用它， 那就把这里改了。
mysql> update mysql.user set authentication_string=PASSWORD('newPwd'), plugin='mysql_native_password' where user='root';#最关键一步骤Query OK, 1 row affected, 1 warning (0.00 sec)Rows matched: 1 Changed: 1 Warnings: 1mysql> flush privileges;Query OK, 0 rows affected (0.00 sec)
重启服务，问题就解决了
~$ sudo service mysql stop...* MySQL Community Server 5.7.10 is stopped~$ sudo service mysql start..* MySQL Community Server 5.7.10 is started~$ mysql -u root -pEnter password: Welcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 2Server version: 5.7.10 MySQL Community Server (GPL)
7.linux云主机端：开启远程连接
sudo nano /etc/mysql/mysql.conf.d/f 注释掉bind-address = 127.0.0.1sudo service mysql restart
