[root@localhost home]# yum install mysql-server
 已加载插件：fastestmirror, langpacks
 Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
 base         | 3.6 kB 00:00:00 
 extras         | 3.4 kB 00:00:00 
 updates         | 3.4 kB 00:00:00 
 (1/4): base/7/x86_64/group_gz      | 155 kB 00:00:01 
 (2/4): extras/7/x86_64/primary_db     | 139 kB 00:00:01 
 (3/4): base/7/x86_64/primary_db      | 5.6 MB 00:00:38 
 (4/4): updates/7/x86_64/primary_db     | 4.7 MB 00:00:39 
 Loading mirror speeds from cached hostfile
 * base: mirrors.163.com
 * extras: mirrors.163.com
 * updates: mirrors.163.com
 没有可用软件包 mysql-server。
 错误：无须任何处理

 systemctl start mariadb #启动MariaDB
 systemctl stop mariadb #停止MariaDB
 systemctl restart mariadb #重启MariaDB
 systemctl enable mariadb #设置开机启动

[root@localhost lzh]# mysql -u root -p
Enter password: 
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 6
Server version: 5.5.52-MariaDB MariaDB Server

Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> show databases;
+--------------------+
| Database  |
+--------------------+
| information_schema |
| mysql  |
| performance_schema |
| test  |
+--------------------+
4 rows in set (0.01 sec)

# wget http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
# rpm -ivh mysql-community-release-el7-5.noarch.rpm
# yum install mysql-community-server

[root@localhost lzh]# mysql -u root 
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.26 MySQL Community Server (GPL)

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database  |
+--------------------+
| information_schema |
| mysql  |
| performance_schema |
| test  |
+--------------------+
4 rows in set (0.01 sec)

mysql> set password for 'root'@'localhost' =password('password');
Query OK, 0 rows affected (0.00 sec)

[root@localhost lzh]# rpm -qa |grep mariadb