251--Client does not support authentication protocol requested by server的解决

转载自：https://blog.csdn.net/XDMFC/article/details/80263215

好不容易安装好mysql，但又出现了mysql客户端版本太低的问题。根据参考的这篇博客，完美的解决了该问题。

1、通过命令行进入解压的mysql根目录下mysql目录下的bin文件夹。

如  F：\>cd  mysql-5.7.23\bin

2、登陆数据库

mysql -uroot -p

3、再输入root的密码：

Enter password: ******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 8.0.11 MySQL Community Server - GPL
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>

4、更改加密方式：

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'password' PASSWORD EXPIRE NEVER;

5、更改密码：该例子中 123为新密码

mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123';

6、刷新：

mysql> FLUSH PRIVILEGES;

这步完成后我已经成功解决了问题。如果报错，可以看下面第7步，博主依然给出了解决方案

7、

// 如果报错ERROR 1396 (HY000): Operation ALTER USER failed for 'root'@'%'：

则是远程访问权限不正确，先选择数据库，查看一下再更改：

mysql> use mysql;
Database changed
 
mysql> select user,host from user;
+------------------+-----------+
| user             | host      |
+------------------+-----------+
| mysql.infoschema | localhost |
| mysql.session    | localhost |
| mysql.sys        | localhost |
| root             | localhost |
+------------------+-----------+
5 rows in set (0.00 sec)

最后，感谢参考的该博主。此次转载只希望帮助更多的人，毕竟在犄角旮旯里找到这个方案不容易。若有人想要转载，请注明原博主，谢谢。真的非常感谢原博主。