下载mysql源安装包
wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
安装mysql源
yum localinstall mysql57-community-release-el7-8.noarch.rpm
检查mysql源是否安装成功
yum repolist enabled | grep "mysql.*-community.*"
修改yum源 【可跳过】
vim /etc/yum.repos.d/mysql-community.repo
改变默认安装的mysql版本。比如要安装5.6版本，将5.7源的enabled=1改成enabled=0。然后再将5.6源的enabled=0改成enabled=1即可。
enabled=1表示即将要安装的mysql版本，这个文件也可以不修改，默认安装mysql最高版本
安装MySQL
yum install mysql-community-server
启动MySQL服务并设置开机启动
systemctl start mysqld
systemctl enable mysqld
systemctl daemon-reload
1、这里如果报错：Failed to start mysqld.service Unit not found
步骤 1：先检查mysqld服务的systemd配置文件是否存在
ls /usr/lib/systemd/system/mysqld.service
如果文件存在，将输出文件路径；如果文件不存在，则需要执行下一步操作。
步骤 2：重新安装MySQL服务器
yum install mysql-server
步骤 3：再次执行：
systemctl start mysqld
2、这里如果报错：The GPG keys listed for the "MySQL 5.7 Community Server" repository are already installed but they are not correct for this package. Check that the correct key URLs are configured for this repository.
运行：rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022
端口开放
firewall-cmd --zone=public --add-port=3306/tcp --permanent
firewall-cmd --reload
修改root本地登录密码
查看mysql密码
grep 'temporary password' /var/log/mysqld.log
连接mysql
mysql -uroot -p
修改密码【注意：后面的分号一定要跟上】
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'newPass123~!';
或者：
mysql> set password for 'root'@'localhost'=password('newPass123~!');
查看当前的密码策略
mysql> show variables like '%password%';
添加远程登录用户
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'youpassword' WITH GRANT OPTION;
以上步骤就已经安装好了Mysql并且可以使用了，其他相关内容：
启动：service mysqld start
关闭：service mysqld stop
重启：service mysqld restart
查看服务状态：service mysqld status
查看MySql系统配置：cat /etc/my.cnf
解决报错：mysql 遇见 Expression #1 of SELECT list is not in GROUP BY clause and … 的问题
select @@global.sql_mode;
set @@global.sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';
测试