数据库忘记密码后重新设置：

1.修改主配置文件，添加 skip-grant-tables，跳过授权表

vim /etc/my.cnf

[root@zhai ~]# vim /etc/my.cnf

[mysqld]
skip-grant-tables
如下图

2.重启mysqld

systemctl restart mysqld

[root@zhai ~]# systemctl restart mysqld

3.无需输入密码进入mysql，执行修改密码的命令，刷新并退出

mysql -u root -p

直接回车进入数据库，无需输入密码
mysql> use mysql;
mysql> update user set authentication_string=password(“123456”) where User=“root”;
mysql> flush privileges;
mysql> quit;

[root@zhai ~]# mysql -u root -pEnter password:Welcome to the MySQL monitor.  Commands end with ; or \\g.Your MySQL connection id is 3Server version: 5.7.17 MySQL Community Server (GPL)Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement.mysql> use mysql;Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -ADatabase changedmysql> update user set authentication_string=password(\"123456\") where User=\"root\";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)mysql> quit;Bye

4.恢复主配置文件，即进入 vim /etc/my.cnf，然后把skip-grant-tables注释掉，最后重启mysqld

systemctl restart mysqld![在这里插入图片描述](https://img-blog.csdnimg.cn/20200722223022258.PNG)

[root@zhai ~]# systemctl restart mysqld[root@zhai ~]# vim /etc/my.cnf[root@zhai ~]# mysql -u root -pEnter password:Welcome to the MySQL monitor.  Commands end with ; or \\g.Your MySQL connection id is 3Server version: 5.7.17 MySQL Community Server (GPL)Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement.