【Mysql 5.7】ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

1、通过mysql -uroot -p，输入密码登录后，必须马上修改密码，否则会报错

2、将密码修改为123456，依然报错

这和mysql 5.7的密码策略（validate_password_policy）有关,validate_password_policy可以取如下值：

默认为1即MEDIUM，包含长度、数字、英文大小写、特殊字符校验。长度由validate_password_length配置，默认为8.

3、在/etc/my.cnf配置文件中增加

4、修改密码为12345678，成功

 5、查看当前密码策略

mysql> show VARIABLES like "%password%"
    -> ;
+---------------------------------------+-------+
| Variable_name                         | Value |
+---------------------------------------+-------+
| default_password_lifetime             | 0     |
| disconnect_on_expired_password        | ON    |
| log_builtin_as_identified_by_password | OFF   |
| mysql_native_password_proxy_users     | OFF   |
| old_passwords                         | 0     |
| report_password                       |       |
| sha256_password_proxy_users           | OFF   |
| 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     |
+---------------------------------------+-------+
14 rows in set (0.01 sec)

default_password_lifetime：密码过期时间（天数），0表示永不过期

validate_password_length：密码长度，默认为8

validate_password_policy：密码复杂度