centos7忘记MySQL密码
1、错误提示如下：
[root@localhost ~]# mysql -u root -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
2、查看一下mysql的进程，是否处于启动状态
[root@localhost ~]# ps -ef | grep -i mysql
mysql 1983 1 0 10:24 ? 00:00:02 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
root 3225 2935 0 10:33 pts/0 00:00:00 grep --color=auto -i mysql
或者
[root@localhost ~]# systemctl status mysqld.service
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: inactive (dead) since 三 2020-08-26 10:34:53 CST; 16s ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Process: 1980 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
Process: 1223 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 1983 (code=exited, status=0/SUCCESS)
3、如果处于启动状态则关闭服务
[root@localhost ~]# /bin/systemctl stop mysqld.service 4、修改MySQL的配置文件my.cnf，查找一下文件的位置
[root@localhost etc]# whereis my.cnf
my: /etc/my.cnf
5、打开 my.cnf文件，加入如下代码
#登录是跳过密码验证
skip-grant-tables
6、重启mysql服务，同时查看状态，看是否启动成功
[root@localhost etc]# systemctl start mysqld.service
[root@localhost etc]# systemctl status mysqld.service
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: active (running) since 三 2020-08-26 10:37:48 CST; 4s ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Process: 3402 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
Process: 3380 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 3405 (mysqld)
Tasks: 27
CGroup: /system.slice/mysqld.service
└─3405 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
7、进入MySQL，提示让输入密码，直接 回车即可。
[root@localhost etc]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.30 MySQL Community Server (GPL)
Copyright (c) 2000, 2020, 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>
8、修改密码，并刷新特权，最后退出。
mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> update mysql.user set authentication_string=password('ryUl1_33au_n0krQ') 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)
mysql> exit;
注意：刚改完密码，我想查看一下MySQL端口号，结果提示错误
[root@localhost etc]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.30
Copyright (c) 2000, 2020, 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> show variables like 'port';
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
mysql> use mysql;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
如上图，根据错误提示，意思就是让执行一下 ALTER USER ，就是在执行（use mysql;）此语句之前，必须使用ALTER USER语句重置密码
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'ryUl1_33au_n0krQ';
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 3306 |
+---------------+-------+
1 row in set (0.00 sec)
如上图，重置一下密码就可以了。最后重新启动一下MySQL服务即可。