1.查询是否有mysql的安装：rpm -qa | grep mysql
查询是否有Mariadb的安装：rpm -qa | grep mariadb
如果有卸载掉：yum -y remove 文件名

2.下载安装包文件 https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.36-1.el7.x86_64.rpm-bundle.tar
通过xftp上传到服务器

mkdir mysql-5.7.36
tar xvf mysql-5.7.36-1.el7.x86_64.rpm-bundle.tar -C ./mysql-5.7.36

rpm -qa | grep mariadb
yum -y remove mariadb-libs.x86_64

3.安装：
rpm -ivh mysql-community-common-5.7.35-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.35-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.35-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.35-1.el7.x86_64.rpm

#4.启动mysql
[root@VM-4-3-centos mysql-5.7.36]# systemctl start mysqld

#5.查看mysql进程
[root@VM-4-3-centos mysql-5.7.36]# ps -ef | grep mysql
mysql 4376 1 2 16:22 ? 00:00:00 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
root 4423 2128 0 16:22 pts/0 00:00:00 grep --color=auto mysql

#6.查看安装密码 root账号,密码：_sKJVHsy&71=
[root@VM-4-3-centos mysql-5.7.36]# cat /var/log/mysqld.log | grep password
2022-06-01T08:22:19.029894Z 1 [Note] A temporary password is generated for root@localhost: _sKJVHsy&71=
[root@VM-4-3-centos mysql-5.7.36]#

7.登录：mysql -u root -p

8.修改密码
修改密码，直接修改会有一个密码复杂度校验，关闭这个校验，编辑文件my.cnf：vim /etc/my.cnf
在[mysqld]下一行加入：validate_password=off
重启mysql服务：systemctl restart mysqld
重新进入sql修改密码：alter user 'root'@'localhost' identified by '123456';

9.更改远程访问：默认禁止(在腾讯云中是由服务器防火墙策略来控制的，需要打开)
1、更改权限，执行语句中账号密码为系统账号密码（mysql下执行）
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'IDENTIFIED BY '123456' WITH GRANT OPTION;

跟vim /etc/my.cnf 文件中增加： bind_address=0.0.0.0  或者 bind_address=* 没有关系，跟网络策略有关系，添加规则之后，客户端sqlyog就可以正常连接了。