1. 按照密码要求先设置一个复杂密码
alter user 'root'@'localhost' identified by 'Abcd1234.';
2. 降低密码复杂度
SET GLOBAL validate_password.policy = LOW;
3. 再次修改成简单密码
alter user 'root'@'localhost' identified by 'abcd1234';
alter user 'root'@'localhost' identified by 'Abcd1234.';
SET GLOBAL validate_password.policy = LOW;
alter user 'root'@'localhost' identified by 'abcd1234';