MySQL8和MySQL5.x创建账号不太一样，MySQL8不允许用grant创建新用户，要先创建账号再设置权限

# 创建用户
create user 'root'@'%' identified by '1';
# 授权
grant all privileges on *.* to 'root'@'%' with grant option;
# 刷新权限
flush privileges;
# 修改密码加密方式（MySQL8默认用caching_sha2_password插件加密）
alter user root identified with mysql_native_password by 'xxx';