centos7.x安装mysql

如果系统是CentOS7.x，则自带的数据库是Mariadb，是Mysql的一个分支，虽然使用上完全兼容，但自从甲骨文收购Mysql后还没有取消开源，那就继续用Mysql吧。

先卸载Mariadb：

[gdcni@server202 ~]$ sudo yum remove mariadb* -y

下载Mysql的yum源：

[gdcni@server202 ~]$ sudo wget -P /home/gdcni http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

安装Mysql的yum源：

[gdcni@server202 ~]$ cd /home/gdcni/

[gdcni@server202 ~]$ sudo rpm -ivh mysql57-community-release-el7-11.noarch.rpm

查看Mysql版本：

[gdcni@server202 ~]$ yum repolist all | grep mysql

mysql-cluster-7.5-community/x86_64 MySQL Cluster 7.5 Community      禁用

mysql-cluster-7.5-community-source MySQL Cluster 7.5 Community - So 禁用

mysql-cluster-7.6-community/x86_64 MySQL Cluster 7.6 Community      禁用

mysql-cluster-7.6-community-source MySQL Cluster 7.6 Community - So 禁用

mysql-connectors-community/x86_64  MySQL Connectors Community       启用:     83

mysql-connectors-community-source  MySQL Connectors Community - Sou 禁用

mysql-tools-community/x86_64       MySQL Tools Community            启用:     79

mysql-tools-community-source       MySQL Tools Community - Source   禁用

mysql-tools-preview/x86_64         MySQL Tools Preview              禁用

mysql-tools-preview-source         MySQL Tools Preview - Source     禁用

mysql55-community/x86_64           MySQL 5.5 Community Server       禁用

mysql55-community-source           MySQL 5.5 Community Server - Sou 禁用

mysql56-community/x86_64           MySQL 5.6 Community Server       禁用

mysql56-community-source           MySQL 5.6 Community Server - Sou 禁用

mysql57-community/x86_64           MySQL 5.7 Community Server       启用:    327

mysql57-community-source           MySQL 5.7 Community Server - Sou 禁用

mysql80-community/x86_64           MySQL 8.0 Community Server       禁用

mysql80-community-source           MySQL 8.0 Community Server - Sou 禁用

可以看到57版本是默认启用的。当然，也可以通过如下命令启用或禁用版本：

[gdcni@server202 ~]$ sudo yum-config-manager --enable mysql57-community

[gdcni@server202 ~]$ sudo yum-config-manager --disable mysql56-community

注意，任何时候只能启动一个版本。

好，现在可以安装并启动Mysql了：

[gdcni@server202 ~]$ sudo yum install mysql-community-server

[gdcni@server202 ~]$ sudo systemctl start mysqld

[gdcni@server202 ~]$ sudo systemctl enable mysqld

[gdcni@server202 ~]$ mysql --version

mysql  Ver 14.14 Distrib 5.7.25, for Linux (x86_64) using  EditLine wrapper

       刚安装完成后首先需要修改root密码，虽然有多种修改方法，但可能都会遇到如下报错：ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

       修改方法为：

1） 先关闭Mysql密码认证，vim /etc/my.cnf，在[mysqld]节点下任意位置添加skip-grant-tables：

[mysqld]

skip-grant-tables

2） 然后重启Mysql：

[gdcni@server202 ~]$ sudo systemctl restart mysqld

3） 现在登录Mysql修改一下密码：

[gdcni@server202 ~]$ mysql -u root

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 2

Server version: 5.7.25 MySQL Community Server (GPL)

 

Copyright (c) 2000, 2019, 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> use mysql;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

 

Database changed

mysql> update user set authentication_string=password('gdcni') where user='root';

Query OK, 1 row affected, 1 warning (0.00 sec)

Rows matched: 1  Changed: 1  Warnings: 1

4） 最后重新打开配置vim /etc/my.cnf，去掉前面加的skip-grant-tables，并重启mysqld即可。现在登录就要这样了：

[gdcni@server202 ~]$ mysql -uroot -pgdcni