MySQL默认root密码查看与修改
1. 查看默认密码
MySQL 5.7 在初始安装后(CentOS7 操作系统)会生成随机初始密码，并在 /var/log/mysqld.log 中有记录，可以通过 cat 命令查看，找 password 关键字
[root@stg-mysql mysqldata]# sudo grep 'temporary password' /var/log/mysqld.log-01-22T06:58:56.317416Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: Xq93pu;e&dO9
2. 如果使用默认密码登录不了，那么可以先关闭MySQL的登录密码校验
修改 /etc/f，在 [mysqld] 小节下添加一行：skip-grant-tables=1让 mysqld 启动时不对密码进行验证
重启 mysqld 服务：systemctl restart mysqld
使用 root 用户登录到 mysql：mysql -u root
3. 修改/设置默认的root密码
mysql -u root -puse mysql;ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456'; # 123456是密码，root 是用户名flush privileges;quit;
若修改时报错：
ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
解决方案：
mysql> flush privileges;Query OK, 0 rows affected (0.00 sec)
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
原因是因为密码设置的过于简单会报错,MySQL有密码设置的规范，具体是与validate_password_policy的值有关,下图表明该值规则
解决方案：先查看密码规则，然后调整你的密码
mysql> SHOW VARIABLES LIKE 'validate_password%';+--------------------------------------+--------+| Variable_name | Value |+--------------------------------------+--------+| validate_password.check_user_name | ON|| validate_password.dictionary_file | || validate_password.length | 8|| validate_password.mixed_case_count | 1|| validate_password.number_count | 1|| validate_password.policy | MEDIUM || validate_password.special_char_count | 1|+--------------------------------------+--------+7 rows in set (0.01 sec)
