1. root先利用原密码登陆

mysql -u root -p
Enter password: *******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.26 MySQL Community Server - GPLCopyright (c) 2000, 2021, Oracle and/or its affiliates.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.

2.原修改方式syntx error

mysql> set password for root@localhost = password('xxxxx');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'password('xxxxxx')' at line 1

3.MySQL 8对应修改方式，修改的是当前登陆用户的password

mysql> set password = 'yyyyyy';
Query OK, 0 rows affected (0.07 sec)mysql>