一、使用rpm包安装
更换阿里yum（个人习惯）
步骤：
1）下载wget
yum install -y wget
2）备份默认的yum
mv /etc/yum.repos.d /etc/yum.repos.d.backup
3）设置新的yum目录
mkdir /etc/yum.repos.d
4）下载阿里yum配置到该目录中
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
5）重建缓存
yum clean all
yum makecache
6）升级所有包（改变软件设置和系统设置，系统版本内核都升级，故需要几分钟耐心等待）
yum update -y
以mysql-5.7.23-1.el7.x86_64.rpm-bundle.tar为例
1.下载
下载地址：
官方：
https://cdn.mysql.com//Downloads/MySQL-5.7/mysql-5.7.23-1.el7.x86_64.rpm-bundle.tar
网易:
http://mirrors.163.com/mysql/Downloads/MySQL-5.7/mysql-5.7.23-1.el7.x86_64.rpm-bundle.tar
可以直接在centos里面用wget命令下载，或者在自己电脑上下完再传上去
2.解开tar包
tar -xvf mysql-5.7.23-1.el7.x86_64.rpm-bundle.tar
3.移除centos7自带的mariadb-libs包，不移除的话安装会出错
yum remove -y mariadb-libs
4.使用yum localinstall命令进行本地安装，按照顺序执行
yum localinstall -y mysql-community-common-5.7.23-1.el7.x86_64.rpm
yum localinstall -y mysql-community-libs-5.7.23-1.el7.x86_64.rpm
yum localinstall -y mysql-community-client-5.7.23-1.el7.x86_64.rpm
yum localinstall -y mysql-community-server-5.7.23-1.el7.x86_64.rpm
yum localinstall -y mysql-community-libs-compat-5.7.23-1.el7.x86_64.rpm
期间yum会自动为我们安装所有的依赖包
5.启动mysql服务并允许开机自启
systemctl start mysqld
systemctl enable mysqld
6.查询mysql生成的临时的管理员账号密码（12位）
grep 'temporary password' /var/log/mysqld.log
7.使用生成的临时密码登录mysql
mysql -uroot -p
#(输入上面的初始密码)
(1)修改密码
alter user root@localhost identified by 'MyNewPass4!';
注意
MySQL的 validate_password 插件是默认安装的。要求密码至少包含一个大写字母，一个小写字母，一个数字和一个特殊字符，并且总密码长度至少为8个字符。如果设置的密码强度不符合要求会报错
(2)降低密码策略强度，然后将密码修改简单一点，便于记忆(不建议在生产环境下这么做)
set global validate_password_policy=0;
#0/LOW：只检查长度;
#1/MEDIUM：检查长度、数字、大小写、特殊字符;
#2/STRONG：检查长度、数字、大小写、特殊字符字典文件。
set global validate_password_length=4; #密码最小长度
set global validate_password_mixed_case_count=0;
#密码至少要包含的小写字母个数和大写字母个数;
set global validate_password_number_count=0;
#密码至少要包含的数字个数
#修改密码：
set password=password('1111');
(3)设置允许远程访问
update mysql.user set host='%' where user='root';
8.设置用户或更改密码后需用flush privileges刷新MySQL的系统权限相关表，否则会出现拒绝访问
flush privileges;
或者exit然后
systemctl restart mysqld;
重启mysql服务也行
官方文档：https://dev.mysql.com/doc/refman/5.7/en/linux-installation-yum-repo.html
二、使用MySQL Yum Repository在centos上安装MySQL
(确保网络畅通)
下载地址：https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
1.下载发行包
wget https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
2.安装MySQL Yum Repository
yum install -y https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
3.安装（期间要联网下载）
yum install mysql-community-server
之后同上第五步及之后的步骤
一键安装：
wget https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
yum localinstall -y mysql57-community-release-el7-11.noarch.rpm
yum install mysql-community-server -y
也可以使用清华大学的mysql源
#配置清华大学的mysql yum源
touch /etc/yum.repos.d/mysql-community.repo
cat > /etc/yum.repos.d/mysql-community.repo <<- "EOF"
[mysql-connectors-community]
name=MySQL Connectors Community
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-connectors-community-el7
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql-tools-community]
name=MySQL Tools Community
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-tools-community-el7
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql57-community]
name=MySQL 5.7 Community Server
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql57-community-el7
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql80-community]
name=MySQL 8.0 Community Server
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql80-community-el7
enabled=0
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
EOF
yum makecache
yum install mysql-community-server -y
一键安装配置shell脚本：
yum install -y wget vim
#更换阿里的源(非必要)
mv /etc/yum.repos.d /etc/yum.repos.d.backup
mkdir /etc/yum.repos.d
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum clean all
yum makecache
yum update -y
#配置清华大学的mysql yum源
touch /etc/yum.repos.d/mysql-community.repo
cat > /etc/yum.repos.d/mysql-community.repo <<- "EOF"
[mysql-connectors-community]
name=MySQL Connectors Community
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-connectors-community-el7
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql-tools-community]
name=MySQL Tools Community
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql-tools-community-el7
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql57-community]
name=MySQL 5.7 Community Server
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql57-community-el7
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
[mysql80-community]
name=MySQL 8.0 Community Server
baseurl=http://mirrors.tuna.tsinghua.edu.cn/mysql/yum/mysql80-community-el7
enabled=0
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
EOF
yum makecache
yum install mysql-community-server -y
systemctl start mysqld
systemctl enable mysqld
passlog=$(grep 'temporary password' /var/log/mysqld.log)
pass=${passlog:${#passlog}-12:${#passlog}}
mysql -uroot -p"${pass}" -e"alter user root@localhost identified by 'QQQqqq111...' " --connect-expired-password
pass=QQQqqq111...
mysql -uroot -p"${pass}" -e"set global validate_password_policy=0;" --connect-expired-password
mysql -uroot -p"${pass}" -e"set global validate_password_length=4;" --connect-expired-password
mysql -uroot -p"${pass}" -e"set global validate_password_mixed_case_count=0;" --connect-expired-password
mysql -uroot -p"${pass}" -e"set global validate_password_number_count=0;" --connect-expired-password
#echo 'enter your mysql password'
#read password
password=1111
mysql -uroot -p"${pass}" -e"set password=password('${password}');" --connect-expired-password
mysql -uroot -p"${password}" -e"update mysql.user set host='%' where user='root';" --connect-expired-password
mysql -uroot -p"${password}" -e"flush privileges;" --connect-expired-password
