mysql :第一次安装典型错误

错误代码：

ERROR 1698 (28000): Access denied for user 'root'@'localhost

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 root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server 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](https://www.baidu.com/s?wd=plugin&tn=24004469_oem_dg&rsv_dl=gh_pl_sl_csd)被修改成了auth_socket，用密码登陆的plugin应该是mysql_native_password。

+-----------+-----------------------+
| user      | plugin                |
+-----------+-----------------------+
| root      | auth_socket           |
| mysql.sys | mysql_native_password |
| dev       | mysql_native_password |
+-----------+-----------------------+
3 rows in set (0.01 sec)</pre>

mysql> update mysql.user set authentication_string=PASSWORD('newPwd'), plugin='mysql_native_password' where user='root';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

重启服务，问题就解决

~$ 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 -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.10 MySQL Community Server (GPL