修改mysql密码复杂度和密码的几种方式

1.查看密码复杂度：

SHOW VARIABLES LIKE 'validate_password%';
mysql> show variables like 'password_require%';
Empty set (0.01 sec)
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name                        | Value |
+--------------------------------------+-------+
| validate_password_check_user_name    | OFF   |
| validate_password_dictionary_file    |       |
| validate_password_length             | 8     |
| validate_password_mixed_case_count   | 1     |
| validate_password_number_count       | 1     |
| validate_password_policy             | LOW   |
| validate_password_special_char_count | 1     |
+--------------------------------------+-------+
7 rows in set (0.00 sec)

修改密码复杂度要求

set global validate_password_policy='LOW';
set global validate_password_length=6;
set global validate_password_mixed_case_count=0;
set global validate_password_special_char_count=0;
flush privileges;

查看Mysql初始密码

查看密码： grep password /var/log/mysqld.log

修改密码的方法：

set password for root@locahost=password('123456');
set password for 用户名@localhost = password('新密码'); 
mysqladmin -u用户名 -p旧密码 password 新密码
alter user 'root'@'localhost' identified by 'AaAa888';
alter user 'root'@'localhost' identified by 'AaAa888!!!'; #mysql5.7.44版本

update user set password=password('123456') where user='root' and host='localhost';

mysql8.0更新用户密码
使用以下命令登录到 MySQL:
$ mysql -u root
使用以下命令更新 root 的密码，并退出 MySQL：

mysql > USE mysql;
mysql > UPDATE user SET authentication_string=PASSWORD("new_password") WHERE User='root';
mysql > FLUSH PRIVILEGES;
mysql > quit;

mysql8.0创建用户并授权

create user 'root'@'%' identified by '123456';
flush privileges;
grant all  on . TO user@'%' with grant option;