检查环境中是否已安装 MySQL
[vagary@vagary ~]$ rpm -qa | grep mysql
[vagary@vagary ~]$
返回空值的话，就说明没有安装 Mysql 。
注意：在新版本的CentOS7中，默认的数据库已更新为了Mariadb，而非 MySQL，所以执行 yum install mysql 命令只是更新Mariadb数据库，并不会安装 Mysql。如果已安装的 MySQL 版本不是想要的版本。需要把原来的 Mysql 卸载。
[vagary@vagary ~]$ yum remove mysql mysql-server mysql-libs mysql-common
[vagary@vagary ~]$ rm -rf /var/lib/mysql
[vagary@vagary ~]$ rm -f /etc/my.cnf
注：这里使用的是yum命令卸载，因为yum命令可以自动删除与mysql相关的依赖；如果使用rpm命令卸载，则还需要手动去删除和mysql相关的文件。
如果是CentOS7版本的，我们再检测一下mariadb，因为mariadb是从mysql来的，是它的一个分支
[root@VM-4-12-centos ~]# rpm -qa |grep -i mariadb
mariadb-libs-5.5.68-1.el7.x86_64
如果存在，也需要清理掉，rpm -e 加上包名，把mariadb包清掉
[root@VM-4-12-centos ~]# rpm -e mariadb-libs-5.5.68-1.el7.x86_64
可以看到用rpm删除会失败，提示有依赖关系的软件需要安装
[vagary@VM-4-12-centos app]$ rpm -e mariadb-libs-5.5.68-1.el7.x86_64
error: Failed dependencies:
libmysqlclient.so.18()(64bit) is needed by (installed) postfix-2:2.10.1-9.el7.x86_64
libmysqlclient.so.18(libmysqlclient_18)(64bit) is needed by (installed) postfix-2:2.10.1-9.el7.x86_64
rpm在删除时，如果显示有依赖关系，就可以用yum remove + 包名来删除mariadb
[root@vagary ~]# yum remove mariadb-libs-5.5.68-1.el7.x86_64
Loaded plugins: fastestmirror, langpacks
Resolving Dependencies
--> Running transaction check
---> Package mariadb-libs.x86_64 1:5.5.68-1.el7 will be erased
--> Processing Dependency: libmysqlclient.so.18()(64bit) for package: 2:postfix-2.10.1-9.el7.x86_64
--> Processing Dependency: libmysqlclient.so.18(libmysqlclient_18)(64bit) for package: 2:postfix-2.10.1-9.el7.x86_64
--> Running transaction check
---> Package postfix.x86_64 2:2.10.1-9.el7 will be erased
--> Finished Dependency Resolution
epel/7/x86_64 | 4.7 kB 00:00:00
epel/7/x86_64/group_gz | 96 kB 00:00:00
epel/7/x86_64/updateinfo | 1.1 MB 00:00:00
epel/7/x86_64/primary_db | 7.0 MB 00:00:01
extras/7/x86_64 | 2.9 kB 00:00:00
os/7/x86_64 | 3.6 kB 00:00:00
updates/7/x86_64 | 2.9 kB 00:00:00
updates/7/x86_64/primary_db | 14 MB 00:00:00
Dependencies Resolved
=========================================================================================================================================
Package Arch Version Repository Size
=========================================================================================================================================
Removing:
mariadb-libs x86_64 1:5.5.68-1.el7 @os 4.4 M
Removing for dependencies:
postfix x86_64 2:2.10.1-9.el7 @os 12 M
Transaction Summary
=========================================================================================================================================
Remove 1 Package (+1 Dependent package)
Installed size: 17 M
Is this ok [y/N]: y
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Warning: RPMDB altered outside of yum.
Erasing : 2:postfix-2.10.1-9.el7.x86_64 1/2
Erasing : 1:mariadb-libs-5.5.68-1.el7.x86_64 2/2
Verifying : 1:mariadb-libs-5.5.68-1.el7.x86_64 1/2
Verifying : 2:postfix-2.10.1-9.el7.x86_64 2/2
Removed:
mariadb-libs.x86_64 1:5.5.68-1.el7
Dependency Removed:
postfix.x86_64 2:2.10.1-9.el7
Complete!
这样就删除完成了
开始安装
使用命令rpm -ivh {-file-name}进行安装操作,ivh中， i-install安装；v-verbose进度条；h-hash哈希校验
按照依赖关系依次安装rpm包 依赖关系依次为：common→libs→client→server
[root@vagary mysql]# ll
total 185388
-rw-r--r-- 1 root root 277604 Mar 29 01:17 01_mysql-community-common-5.7.16-1.el7.x86_64.rpm
-rw-r--r-- 1 root root 2237116 Mar 29 01:17 02_mysql-community-libs-5.7.16-1.el7.x86_64.rpm
-rw-r--r-- 1 root root 2112700 Mar 29 01:17 03_mysql-community-libs-compat-5.7.16-1.el7.x86_64.rpm
-rw-r--r-- 1 root root 25034716 Mar 29 01:17 04_mysql-community-client-5.7.16-1.el7.x86_64.rpm
-rw-r--r-- 1 root root 159295840 Mar 29 01:17 05_mysql-community-server-5.7.16-1.el7.x86_64.rpm
-rw-r--r-- 1 root root 872303 Mar 29 01:16 mysql-connector-java-5.1.27-bin.jar
第一个：
[root@vagary mysql]# rpm -ivh 01_mysql-community-common-5.7.16-1.el7.x86_64.rpm
warning: 01_mysql-community-common-5.7.16-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-common-5.7.16-1.e################################# [100%]
第二个：
[root@vagary mysql]# rpm -ivh 02_mysql-community-libs-5.7.16-1.el7.x86_64.rpm
warning: 02_mysql-community-libs-5.7.16-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-libs-5.7.16-1.el7################################# [100%]
第三个：
[root@vagary mysql]# rpm -ivh 03_mysql-community-libs-compat-5.7.16-1.el7.x86_64.rpm
warning: 03_mysql-community-libs-compat-5.7.16-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-libs-compat-5.7.1################################# [100%]
第四个：
[root@vagary mysql]# rpm -ivh 04_mysql-community-client-5.7.16-1.el7.x86_64.rpm
warning: 04_mysql-community-client-5.7.16-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-client-5.7.16-1.e################################# [100%]
第五个：
[root@vagary mysql]# rpm -ivh 05_mysql-community-server-5.7.16-1.el7.x86_64.rpm
warning: 05_mysql-community-server-5.7.16-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
启停Mysql服务
启动服务
[root@vagary lib]# systemctl start mysqld.service
查看服务
[root@vagary lib]# systemctl status mysqld.service
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: active (running) since Tue 2022-03-29 01:52:21 CST; 12s ago
Process: 1841 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
Process: 1741 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 1845 (mysqld)
CGroup: /system.slice/mysqld.service
└─1845 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
Mar 29 01:52:17 vagary systemd[1]: Starting MySQL Server...
Mar 29 01:52:21 vagary systemd[1]: Started MySQL Server.
关闭服务
[root@vagary lib]# systemctl stop mysqld.service
查看进程
查看mysql进程
[root@vagary ~]# ps -ef|grep mysq
mysql 3868 1 8 02:06 ? 00:00:00 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
root 3915 3434 0 02:06 pts/6 00:00:00 grep --color=auto mysq
查看3306端口
[root@vagary ~]# netstat -anop|grep 3306
tcp6 0 0 :::3306 :::* LISTEN 3868/mysqld off (0.00/0/0)
登陆mysql修改root密码
由于MySQL5.7.4之前的版本中默认是没有密码的，登录后直接回车就可以进入数据库，进而进行设置密码等操作。其后版本对密码等安全相关操作进行了一些改变，在安装过程中，会在安装日志中生成一个临时密码。
[root@vagary ~]# grep 'temporary password' /var/log/mysqld.log
2022-03-28T17:52:18.191203Z 1 [Note] A temporary password is generated for root@localhost: Qqlwwy:YJ2o#
则Qqlwwy:YJ2o#为临时密码
登录MySQL
[root@vagary ~]# mysql -uroot -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
这种情况再输入一次就可以了
修改密码
mysql> alter user root@localhost identified by '123456';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql> set password for root@localhost=password('abc123@');
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
密码不能设置太简单了，需要复杂一些的
退出MySQL
mysql> quit;
Bye
这样就安装完成了~
