mysql单实例root密码找回方法：

a 停止mysql服务

[root@db02 data]# /etc/init.d/mysqld stop

Shutting down MySQL.. SUCCESS!

b 使用--skip-grant-tables启动mysql，忽略授权登录验证

[root@db02 data]# mysqld_safe --skip-grant-tables --user=mysql >/dev/null 2>&1 &

[1] 30246

c 登录mysql，修root密码

[root@db02 data]# mysql

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.34 Source distribution

Copyright (c) 2000, 2016, 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> UPDATE mysql.user SET password=PASSWORD("123") WHERE user='root' and host='localhost';

Query OK, 0 rows affected (0.00 sec)

Rows matched: 1  Changed: 0  Warnings: 0

mysql> flush privileges;

Query OK, 0 rows affected (0.01 sec)

d 退出mysql，并且重新启动mysql

mysql> quit

Bye

[root@db02 data]# /etc/init.d/mysqld stop

Shutting down MySQL.. SUCCESS!

[1]+  Done                    mysqld_safe --skip-grant-tables --user=mysql > /dev/null 2>&1

[root@db02 data]# /etc/init.d/mysqld start

Starting MySQL. SUCCESS!

E 进行登陆查看

[root@db02 data]# mysql -uroot -p123

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.34 Source distribution

Copyright (c) 2000, 2016, 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>