Centos安装MySql

下载mysql的RPM包
wget https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm
or
wget http://dev.mysql.com/get/mysql57-community-release-el6-10.noarch.rpm

安装mysql源
sudo yum localinstall mysql80-community-release-el7-1.noarch.rpm
or
sudo yum localinstall mysql57-community-release-el6-10.noarch.rpm
检查源是否安装成功
yum repolist enabled | grep "mysql.-community."

安装mysql
sudo yum install mysql-community-server

启动mysql服务
sudo systemctl start mysqld
or
sudo service mysqld start

设置卡机启动
sudo systemctl enable mysqld
sudo systemctl daemon-reload

or
sudo chkconfig mysqld on

修改root本地登录密码（mysql安装完成之后，在/var/log/mysqld.log文件中给root生成了一个默认密码）

查看默认(临时)密码
grep 'temporary password' /var/log/mysqld.log
默认密码<================>*jBh+C/lh9K0

进入修改密码
mysql -u root -p
======================================================================
修改密码策略
set global validate_password.policy=0;
set global validate_password.length=4;

or
set global validate_password_policy=0;
======================================================================
修改密码
ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';

ALTER USER 'root'@'localhost' IDENTIFIED BY '123456.';

完成

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查看mysqsl状态
systemctl status mysqld