centos7下rpm安装mysql5.7

rpm -ivh mysql-community-common-5.7.22-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.22-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.22-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.22-1.el7.x86_64.rpm

systemctl start mysqld.service    启动mysql
systemctl status mysqld.service  查看mysql状态
systemctl stop mysqld.service   关闭mysql

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

更改策略，设置 validate_password_policy=0;
mysql> set global validate_password_policy=0;    # 此时，新密码长度大于等于8位才有效，否则报错
修改有效密码长度：

mysql> set global validate_password_length=1;
Query OK, 0 rows affected (0.00 sec)
不管设置  validate_password_length=1,还是2,3,4 ,‘使密码长度生效’这个参数的实际值都是4。超过4后设置是多少实际就是多少。

step2：重设密码：
mysql> set password for root@localhost=password('9527');