MySQL 8.0 以上版本重置 root 用户密码

1. 在 /etc/my.cnf 文件末尾追加 skip-grant-tables

   1 [root@abdefg mysql]# vim /etc/my.cnf
   2 [mysql]
   3 # 设置mysql客户端默认字符集
   4 default-character-set=utf8mb4 
   5
   6 [mysqld]
   7 # 设置3306端口
   8 port = 3306 
   9 # 设置mysql的安装目录
   10 basedir=/usr/local/mysql
   11 # 设置mysql数据库的数据的存放目录
   12 datadir=/usr/local/mysql/data
   13 # 允许最大连接数
   14 max_connections=200
   15 # 服务端默认编码（数据库级别）
   16 character-set-server=utf8mb4
   17 # 创建新表时将使用的默认存储引擎
   18 default-storage-engine=INNODB 
   19 lower_case_table_names=1
   20 max_allowed_packet=16M
   21 skip-grant-tables
   

2. 重启MySQL服务

    [root@abdefg mysql]# service mysqld restart
   

3. 免密码登录 root 用户（输入密码时直接回车即可）

   1 [root@abdefg bin]# mysql -uroot -p
   2 Enter password: 
   3 Welcome to the MySQL monitor.  Commands end with ; or \g.
   4 Your MySQL connection id is 8
   5 Server version: 8.0.13 MySQL Community Server - GPL
   6
   7 Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
   8
   9 Oracle is a registered trademark of Oracle Corporation and/or its
   10 affiliates. Other names may be trademarks of their respective
   11 owners.
   12
   13 Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
   14
   15 mysql> 
   

4. 重置密码

    mysql> use mysql
   

   查询一下

    mysql> select host, user, authentication_string, plugin from user;
   

   执行修改报错

   1 mysql> alter user 'root'@'localhost'IDENTIFIED BY 'newpassword[@123](https://my.oschina.net/u/9520)';
   2 ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
   

   先执行flush privileges;然后会alter成功，要不然会alter失败

   1 mysql> flush privileges;
   2 Query OK, 0 rows affected (0.00 sec)
   3
   4 mysql> alter user 'root'@'localhost'IDENTIFIED BY 'newpassword[@123](https://my.oschina.net/u/9520)';
   5 Query OK, 0 rows affected (0.03 sec)
   6
   7 mysql> exit
   8 Bye
   

5. 把/etc/my.cnf 文件末尾的 skip-grant-tables 去掉，重启MySQL服务，修改完成

参考文档：网络蚂蚁 奥斯维克鸡腿学徒