You must reset your password using ALTER USER statement before executing this statement. - 好文

MySQL 5.7之后，刚初始化的MySQL实例要求先修改密码。否则会报错：
mysql> create database test; ERROR 1820 (HY000): You must reset your password
using ALTER USER statement before executing this statement.
所以修改下密码就OK：
alter user root@localhost identified by 'P@ssword1!'; flush privileges;