MYSQL再学习1-Centos安装mysql5.7

博主最近再看数据库，分享一下mysql相关的经验，强烈建议从官网文档学习！！！

一、环境准备和相关参考

机器	Centos7.8
网络	已连接外网
mysql官网	https://www.mysql.com/cn/
官网安装指南5.7	https://dev.mysql.com/doc/refman/5.7/en/linux-installation-yum-repo.html

RPM包：

二、检查是否安装mysql和mariadb，卸载相关，防止后续安装出错

rpm -qa | grep mariadb
rpm -qa | grep mysql

yum remove -y  mariadb-libs-5.5.65-1.el7.x86_64

三、获取最新官方源，这样可以下载最新的官方rpm包

#把文件下载到home下的soft文件夹
cd /home/soft
wget https://repo.mysql.com//mysql80-community-release-el7-5.noarch.rpm

#本地安装
yum localinstall mysql80-community-release-el7-5.noarch.rpm

#更新源并查询是否安装成功
yum clean all && yum makecache

#查询是否存在mysql的相关包
yum repolist enabled | grep "mysql.*-community.*"
yum repolist all | grep mysql

四、启用mysql5.7源，这次安装mysql5.7版本

yum -y install yum-utils
#启用mysql5.7，禁用mysql8.0
yum-config-manager --disable mysql80-community 
yum-config-manager --enable mysql57-community
yum repolist all | grep mysql

五、安装mysql5.7版本

yum install mysql-community-server -y
#虽然只有一条命令，但是安装的时候回帮你把相应的工具都装了

#这将安装 MySQL 服务器的软件包 ( mysql-community-server) 以及运行服务器所需的组件的软件包，
包括客户端的软件包 ( mysql-community-client)、
客户端和服务器的常见错误消息和字符集 ( mysql-community-common) 
以及共享的客户端库 ( mysql-community-libs)

相关安装记录

[root@paas6 soft]# yum install mysql-community-server -y
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * elrepo: hkg.mirror.rackspace.com
正在解决依赖关系
--> 正在检查事务
---> 软件包 mysql-community-server.x86_64.0.5.7.37-1.el7 将被 安装
--> 正在处理依赖关系 mysql-community-common(x86-64) = 5.7.37-1.el7，它被软件包 mysql-community-server-5.7.37-1.el7.x86_64 需要
--> 正在处理依赖关系 mysql-community-client(x86-64) >= 5.7.9，它被软件包 mysql-community-server-5.7.37-1.el7.x86_64 需要
--> 正在检查事务
---> 软件包 mysql-community-client.x86_64.0.5.7.37-1.el7 将被 安装
--> 正在处理依赖关系 mysql-community-libs(x86-64) >= 5.7.9，它被软件包 mysql-community-client-5.7.37-1.el7.x86_64 需要
---> 软件包 mysql-community-common.x86_64.0.5.7.37-1.el7 将被 安装
--> 正在检查事务
---> 软件包 mysql-community-libs.x86_64.0.5.7.37-1.el7 将被 安装
--> 解决依赖关系完成

依赖关系解决

=========================================================================================================================
 Package                             架构                版本                       源                              大小
=========================================================================================================================
正在安装:
 mysql-community-server              x86_64              5.7.37-1.el7               mysql57-community              174 M
为依赖而安装:
 mysql-community-client              x86_64              5.7.37-1.el7               mysql57-community               25 M
 mysql-community-common              x86_64              5.7.37-1.el7               mysql57-community              311 k
 mysql-community-libs                x86_64              5.7.37-1.el7               mysql57-community              2.4 M

事务概要
=========================================================================================================================
安装  1 软件包 (+3 依赖软件包)

总下载量：202 M
安装大小：878 M
Downloading packages:
警告：/var/cache/yum/x86_64/7/mysql57-community/packages/mysql-community-common-5.7.37-1.el7.x86_64.rpm: 头V4 RSA/SHA256 Signature, 密钥 ID 3a79bd29: NOKEY
mysql-community-common-5.7.37-1.el7.x86_64.rpm 的公钥尚未安装
(1/4): mysql-community-common-5.7.37-1.el7.x86_64.rpm                                             | 311 kB  00:00:02     
(2/4): mysql-community-libs-5.7.37-1.el7.x86_64.rpm                                               | 2.4 MB  00:00:01     
(3/4): mysql-community-client-5.7.37-1.el7.x86_64.rpm                                             |  25 MB  00:00:07     
(4/4): mysql-community-server-5.7.37-1.el7.x86_64.rpm                                             | 174 MB  00:00:32     
-------------------------------------------------------------------------------------------------------------------------
总计                                                                                     5.6 MB/s | 202 MB  00:00:36     
从 file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql-2022 检索密钥
导入 GPG key 0x3A79BD29:
 用户ID     : "MySQL Release Engineering <mysql-build@oss.oracle.com>"
 指纹       : 859b e8d7 c586 f538 430b 19c2 467b 942d 3a79 bd29
 软件包     : mysql80-community-release-el7-5.noarch (@/mysql80-community-release-el7-5.noarch)
 来自       : /etc/pki/rpm-gpg/RPM-GPG-KEY-mysql-2022
从 file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql 检索密钥
导入 GPG key 0x5072E1F5:
 用户ID     : "MySQL Release Engineering <mysql-build@oss.oracle.com>"
 指纹       : a4a9 4068 76fc bd3c 4567 70c8 8c71 8d3b 5072 e1f5
 软件包     : mysql80-community-release-el7-5.noarch (@/mysql80-community-release-el7-5.noarch)
 来自       : /etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  正在安装    : mysql-community-common-5.7.37-1.el7.x86_64                                                           1/4 
  正在安装    : mysql-community-libs-5.7.37-1.el7.x86_64                                                             2/4 
  正在安装    : mysql-community-client-5.7.37-1.el7.x86_64                                                           3/4 
  正在安装    : mysql-community-server-5.7.37-1.el7.x86_64                                                           4/4 
  验证中      : mysql-community-server-5.7.37-1.el7.x86_64                                                           1/4 
  验证中      : mysql-community-libs-5.7.37-1.el7.x86_64                                                             2/4 
  验证中      : mysql-community-common-5.7.37-1.el7.x86_64                                                           3/4 
  验证中      : mysql-community-client-5.7.37-1.el7.x86_64                                                           4/4 

已安装:
  mysql-community-server.x86_64 0:5.7.37-1.el7

六、安装完成后，启动mysql，查看版本，设置root密码

#启动并设置开机自启
systemctl start mysqld
systemctl enable mysqld
systemctl status mysqld

#查看版本
mysql --version
mysql  Ver 14.14 Distrib 5.7.37, for Linux (x86_64) using  EditLine wrapper

#查看初始root密码，并重新设置
grep 'temporary password' /var/log/mysqld.log
2022-02-14T03:31:21.363571Z 1 [Note] A temporary password is generated for root@localhost: H1(yRxS!js_u
初始密码:H1(yRxS!js_u

#登录mysql，并重新设置root密码
mysql -u root -p
输入初始密码

格式：mysql> set password for 用户名@localhost = password('新密码'); 
或者使用：ALTER USER 'root'@'localhost' IDENTIFIED BY 'root-password';

例子：mysql> set password for root@localhost = password('Subsea@123');
#注意密码尽量设置复杂一点，安全一下。如果想修改简单密码，百度一下

七、设置允许远程登录，使用软件远程访问mysql

#查看当前数据库
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

#设置允许远程
mysql> use mysql;

mysql> select user,host from user;

mysql> update user set host="%" where user="root";

#刷新权限
mysql> flush privileges;