wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm

yum localinstall mysql57-community-release-el7-8.noarch.rpm

yum repolist enabled | grep "mysql.*-community.*"

vim /etc/yum.repos.d/mysql-community.repo

非必选，简单看看了解了解就行。

yum install mysql-community-server

systemctl start mysqld

systemctl status mysqld.service

systemctl enable mysqld

systemctl daemon-reload

9.1 查看mysql root默认密码

grep "password" /var/log/mysqld.log

mysql -uroot -p

ALTER USER 'root'@'localhost' IDENTIFIED BY 'NewPass4!@Test';

注意：如果输入grep查看原始密码以后没有反应，就可以通过下列方法修改mysql默认密码。

通过添加软连接

mkdir -pv /var/lib/mysql

ln -s /tmp/mysql.sock /var/lib/mysql/mysql.sock

mysql

修改密码语句根据版本区分：

• MySQL5.7以下版本 UPDATE mysql.user SET Password=PASSWORD('新密码') where USER='root';

• MySQL5.7及以上版本 update mysql.user set authentication_string=password('root') where user='root'

10.1 添加readonly用户

GRANT SElECT ON *.* TO 'username'@'%' IDENTIFIED BY "password";

flush privileges;

10.2 添加可读可写用户

grant all privileges on *.* to root@localhost identified by 'mysql';

flush privileges;