下载地址：
https://dev.mysql.com/downloads/mysql/
选择

1.解压mysql-8.0.12-linux-glibc2.12-x86_64.tar.xz

xz -d mysql-8.0.12-linux-glibc2.12-x86_64.tar.xz 

生成mysql-8.0.12-linux-glibc2.12-x86_64.tar

tar -xvf mysql-8.0.12-linux-glibc2.12-x86_64.tar

2.重命名解压后生成的mysql-8.0.12-linux-glibc2.12-x86_64

mv mysql-8.0.12-linux-glibc2.12-x86_64 mysql8.0.12

3.创建mysql的data目录

mkdir /home/mysql/data 

4.初始化数据库

cd /home/mysql/software/mysql8.0.12/bin./mysqld --user=mysql --basedir=/home/mysql/software/mysql8.0.12 --datadir=/home/mysql/data  --initialize

初始化后会生成临时的一个数据库密码，记录下来 root@localhost: TfM%zKi&p46
2020-05-14T03:47:30.602779Z 6 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: TfM%zKi&p46
5.在/etc/创建my.cnf 配置文件

touch my.cnf

内容为：[mysqld]下的basedir和datadir修改为自己的对应的目录
basedir为数据库安装路径，datadir为数据库数据路径，log-error和pid-file为日志和pid路径

[mysql]
default-character-set=utf8
socket=/var/lib/mysql/mysql.sock[mysqld]
skip-name-resolve
port=3306
socket=/var/lib/mysql/mysql.sockbasedir=/home/mysql/app/mysql8.0.20
datadir=/home/mysql/datamax_connections=200
character-set-server=utf8
default-storage-engine=INNODB
max_allowed_packet=16M[mysqld_safe]
log-error=/home/mysql/log/mysql.log
pid-file=/home/mysql/run/mysql.pid

5.1 创建对应的mysql.log和mysql.pid 修改权限

chmod 750 /var/log/mysql/mysql.log
chmod 750 /var/run/mysql/mysql.pid

6.启动命令加入到系统服务service管理中

cd /home/mysql/software/mysql8.0.12/support-files
cp mysql.server /etc/init.d/mysqld
chmod 755 /etc/init.d/mysqld

7.配置环境变量
把mysql的命令添加到path中，修改/etc/profile文件，在这个文件的最后面添加一行

export MYSQL_HOME=/home/mysql/software/mysql8.0.12
export PATH=$PATH:$MYSQL_HOME/bin

执行source /etc/profile,使path生效

source /etc/profile

8.启动MySQL服务

sudo service mysqld start 启动
sudo service mysqld restart 重启
sudo service mysqld stop 停止

9.登陆mysql，输入初始化生成的密码

mysql -u root -p

10.修改root密码
见下方的修改密码处详解

修改root密码
1、在/etc/my.cnf文件夹中的 [mysqld] 的后面添加skip-grant-tables；跳过登入权限验证；

[mysqld]
port=3306
user=mysql
socket=/tmp/mysql/mysql.sock
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data

添加跳过验证（修改后重启，修改完后删除再重启）

skip-grant-tables

重启msyql服务 （使修改的配置生效）

service mysqld restart

2、直接连接是数据 用（mysql -u root）直接连上数据库：
（如果还是报密码错误，修改的配置文件没有生效，查询是否修改错误，然后再次重启服务）；
mysql> use mysql;

#先把密码置为空字符串；（不让后面修改密码会报错）
mysql> update user set authentication_string="" where user="root";

#这个刷新非常有必要；不让后面执行alter就会出错

mysql> flush privileges;
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'root';

查看mysql版本

SELECT VERSION();

18.给root用户赋权限，将用户的host从locahost（本地访问）改为%（远程访问）

GRANT ALL ON *.* TO 'root'@'%';

如果执行此命令报没有权限，则重新创建一个root用户host为%
CREATE USER 'root'@'%' IDENTIFIED BY 'root'; --创建root用户，host为%
19.给%的root用户赋所有权限

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION; 

20.修改root用户密码规则

ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY 'root'; 

删除库中所有表但是不删库sql脚本：

SELECTCONCAT('droptable',table_name,';')FROMinformation_schema.`TABLES`WHEREtable_schema='activitiDB';

添加/etc/init.d/mysqld到服务

chkconfig mysqld on

修改mysqld脚本中的basedir 和datadir

systemctl start mysqld.service

启动mysql失败

5月 14 12:04:21 localhost.CentOS8 setroubleshoot[8346]: SELinux is preventing /usr/bin/bash from execute_no_trans access on the file /home/mysql/ap>
5月 14 12:04:21 localhost.CentOS8 platform-python[8346]: SELinux is preventing /usr/bin/bash from execute_no_trans access on the file /home/mysql/a>

Plugin catchall (100. confidence) suggests **************************
If you believe that bash should be allowed execute_no_trans access on the mysqld_safe fil>
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c ‘mysqld’ --raw | audit2allow -M my-mysqld
# semodule -X 300 -i my-mysqld.pp

解决方法：

ausearch -c 'mysqld' --raw | audit2allow -M my-mysqld
semodule -X 300 -i my-mysqld.pp

[root@localhost init.d]# systemctl start mysqld.service
Warning: The unit file, source configuration file or drop-ins of mysqld.service changed on disk. Run ‘systemctl daemon-reload’ to reload units.
Job for mysqld.service failed because the control process exited with error code.
See “systemctl status mysqld.service” and “journalctl -xe” for details.

解决方法：

systemctl daemon-reload

5月 14 12:08:58 localhost.CentOS8 setroubleshoot[8584]: SELinux is preventing mysqld_safe from ioctl access on the file /home/mysql/app/mysql8.0.20>
5月 14 12:08:58 localhost.CentOS8 platform-python[8584]: SELinux is preventing mysqld_safe from ioctl access on the file /home/mysql/app/mysql8.0.2>

Plugin catchall (100. confidence) suggests * If you believe that mysqld_safe should be allowed ioctl access on the mysqld_safe file by>
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c ‘mysqld_safe’ --raw | audit2allow -M my-mysqldsafe
# semodule -X 300 -i my-mysqldsafe.pp
解决方法：

ausearch -c 'mysqld_safe' --raw | audit2allow -M my-mysqldsafe
semodule -X 300 -i my-mysqldsafe.pp

5月 14 12:10:03 localhost.CentOS8 setroubleshoot[8739]: SELinux is preventing /home/mysql/app/mysql8.0.20/bin/my_print_defaults from map access on >
5月 14 12:10:03 localhost.CentOS8 platform-python[8739]: SELinux is preventing /home/mysql/app/mysql8.0.20/bin/my_print_defaults from map access on>

Plugin catchall_boolean (89.3 confidence) suggests If you want to allow domain to can mmap files
Then you must tell SELinux about this by enabling the ‘domain_can_mmap_files’ booleanDo
setsebool -P domain_can_mmap_files 1

Plugin catchall (11.6 confidence) suggests
If you believe that my_print_defaults should be allowed map access on the my_print_defaul>
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c ‘my_print_defaul’ --raw | audit2allow -M my-myprintdefaul
# semodule -X 300 -i my-myprintdefaul.pp

解决方法：

ausearch -c 'my_print_defaul' --raw | audit2allow -M my-myprintdefaul
semodule -X 300 -i my-myprintdefaul.pp

Starting MySQL.2020-05-14T04:11:24.576292Z mysqld_safe Directory ‘/var/lib/mysql’ for UNIX socket f>
5月 14 12:11:25 localhost.CentOS8 mysqld[8872]: ERROR! The server quit without updating PID file (/home/mysql/data/localhost.CentOS8.pid).
5月 14 12:11:25 localhost.CentOS8 systemd[1]: mysqld.service: Control process exited, code=exited status=1

selinux惹的祸，如果是centos系统，默认会开启selinux
解决方法：
关闭它，打开/etc/selinux/config，把SELINUX=enforcing改为SELINUX=disabled后存盘退出重启机器

Could not create unix socket lock file /var/lib/mysql/mysql.sock.lock.
解决方法 ：

chown -R mysql:mysql /var/lib/mysql
chown -R mysql:mysql /home/mysql/data

执行后

在线安装

1.linux可以连网情况下
1.1 wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm下载rpm镜像源
1.2yum -y install mysql57-community-release-el7-10.noarch.rpm安装镜像源
1.3yum -y install mysql-community-server安装
1.4systemctl start mysqld.service启动mysql
1.5grep “password” /var/log/mysqld.log查看密码
1.6ALTER USER ‘root’@‘localhost’ IDENTIFIED BY ‘PassW0rd.’;修改密码
1.7SHOW VARIABLES LIKE ‘validate_password%’;查看密码校验规则
1.8set global validate_password_policy=0; 设置校验规则
1.9set global validate_password_length=1; 设置校验规则
1.10这个时候就可以设置简单密码了
1.11修改远程访问grant all privileges on . to root@’%’ identified by “123456”;
2.没有网络的情况下
2.1 使用其它有网的电脑下载社区版本https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.24-linux-glibc2.12-x86_64.tar.gz，然后想办法吧安装包拷贝到服务器上。
2.2检查是否安装了mysql：rpm -qa | grep mysql卸载安装的：rpm -e 已经存在的MySQL全名
2.3解压文件到指定位置
2.4复制或创建my.cnf文件到/etc下
2.5复制support-files下的mysql.server到/etc/init.d目录下
2.6初始化mysql库到mysql的bin目录下./mysqld --initialize --user=mysql --basedir=/home/mysql/mysql --datadir=/home/mysql/mysql/data
2.7查看初始密码grep ‘password’ /var/log/mysqld.log |head -n 1
2.8启动mysql ./mysqld_safe –user=mysql