mysql 报错ERROR 1820 (HY000):You must resetpassword

今天登录mysql（Server version: 5.7.11） 还是很好的，今天登录后执行任何命令都报下面的错误

mysql> help contents
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
mysql> help contents
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
mysql> show databases;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

解决办法
1、 修改用户密码
mysql> alter user 'root'@'localhost' identified by 'youpassword';  

或者       

mysql> set password=password("youpassword");
2、刷新权限
mysql> flush privileges;

mysql> help contents
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the following
categories:
   Account Management
   Administration
   Compound Statements
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
   Help Metadata
   Language Structure
   Plugins
   Procedures
   Storage Engines
   Table Maintenance
   Transactions
   User-Defined Functions
   Utility
mysql> show databases
-> ^C
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.01 sec)

mysql>
mysql>

问题解决，希望能帮助到大家。