CentOS7.2下安裝MySQL

一、系統環境
[root@localhost home]# cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)

二、mysql安裝
安裝mysql和mysql-devel都成功，但是安裝mysql-server失敗，如下：

[root@localhost home]# yum install mysql-server
已加載插件：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
  沒有可用軟件包 mysql-server。
  錯誤：無須任何處理
  出現這樣問題是CentOS 7 版本將MySQL數據庫軟件從默認的程序列表中移除，用mariadb代替了

有兩種解決辦法：

1、方法一：安裝mariadb

MariaDB數據庫管理系統是MySQL的一個分支，採用GPL授權許可 MariaDB的目的是完全兼容MySQL，包括API和命令行，使之能輕鬆成爲MySQL的代替品。MariaDB由MySQL的創始人Michael Widenius（英語：Michael Widenius）主導開發，他早前將自己創建的公司MySQL AB賣給了SUN，此後，隨着SUN被甲骨文收購，MySQL的所有權也落入Oracle的手中。MariaDB名稱來自Michael Widenius的女兒Maria的名字。

安裝mariadb，輸入安裝命令

[root@localhost home]# yum install mariadb-server mariadb

mariadb數據庫的相關命令是：

systemctl start mariadb #啓動MariaDB

systemctl stop mariadb #停止MariaDB

systemctl restart mariadb #重啓MariaDB

systemctl enable mariadb #設置開機啓動

先啓動數據庫

[root@yl-web yl]# systemctl start mariadb

默認無密碼

[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)
2、方法二：官網下載安裝mysql-server

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****

安裝成功後重啓mysql服務

# service mysqld restart

初次安裝mysql，root賬戶沒有密碼

[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)
設置密碼

mysql> set password for 'root'@'localhost' =password('password');
Query OK, 0 rows affected (0.00 sec)
安裝完以後mariadb自動就被替換了，將不再生效。

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