1.查詢是否有mysql的安裝：rpm -qa | grep mysql
查詢是否有Mariadb的安裝：rpm -qa | grep mariadb
如果有解除安裝掉：yum -y remove 檔名

2.下載安裝包檔案 https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.36-1.el7.x86_64.rpm-bundle.tar
通過xftp上傳到伺服器

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

#5.檢視mysql程序
[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.檢視安裝密碼 root賬號,密碼：_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.登入：mysql -u root -p

8.修改密碼
修改密碼，直接修改會有一個密碼複雜度校驗，關閉這個校驗，編輯檔案my.cnf：vim /etc/my.cnf
在[mysqld]下一行加入：validate_password=off
重啟mysql服務：systemctl restart mysqld
重新進入sql修改密碼：alter user 'root'@'localhost' identified by '123456';

9.更改遠端訪問：預設禁止(在騰訊雲中是由伺服器防火牆策略來控制的，需要開啟)
1、更改許可權，執行語句中賬號密碼為系統賬號密碼（mysql下執行）
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'IDENTIFIED BY '123456' WITH GRANT OPTION;

跟vim /etc/my.cnf 檔案中增加： bind_address=0.0.0.0  或者 bind_address=* 沒有關係，跟網路策略有關係，新增規則之後，客戶端sqlyog就可以正常連線了。