linux mysql升级8，Java面试题库
1.3解压
tar -xvf mysql-8.0.15-1.el7.x86_64.rpm-bundle.tar
2.删除原mysql
2.1查询安装的mysql并删除
rpm -qa |grep mysql -i
查询出来的都删除
rpm -e --nodeps ***
2.2删除残余
whereis mysql
查询出来的都删除
rm -rf /usr/bin/mysql /usr/lib64/mysql /usr/share/man/man1/mysql.1.gz
2.3删库（2.4不是跑路，因为之前安装过mysql,如果之前没有安装过，不用清理）
rm -rf /var/lib/mysql
2.4.删除日志(只安装不启动这个文件有，但是文件是没有内容的）
rm -rf /var/log/mysqld.log
3.安装
3.1安装必选项（按照顺序，我是一次性安装的，和分开安装没啥区别，省事儿一点）
首先安装common
然后安装lib
接着安装client
最后安装server
rpm -ivh mysql-community-common-8.0.15-1.el7.x86_64.rpm mysql-community-libs-8.0.15-1.el7.x86_64.rpm mysql-community-client-8.0.15-1.el7.x86_64.rpm mysql-community-server-8.0.15-1.el7.x86_64.rpm
如果有报错
error: Failed dependencies:
perl(JSON) is needed by mysql-community-test-8.0.15-1.el7.x86_64
解决方案：
yum install perl.x86_64 perl-devel.x86_64 -y
yum install perl-JSON.noarch -y
3.2 安装非必选项（可不安装，按照顺序）
rpm -ivh mysql-community-libs-compat-8.0.15-1.el7.x86_64.rpm
rpm -ivh mysql-community-embedded-compat-8.0.15-1.el7.x86_64.rpm
rpm -ivh mysql-community-devel-8.0.15-1.el7.x86_64.rpm
rpm -ivh mysql-community-test-8.0.15-1.el7.x86_64.rpm
安装完成
4.启动
4.1启动mysql
sevice mysqld start
5.设置密码
不修改密码登录后是不能操作的
例如：
mysql> use mysql
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
修改密码有两种方式
1.利用生成的出手四化密码登录,然后修改
初始化密码在/var/log/mysqld.log
例如：
2019-05-31T02:08:01.273665Z 0 [System] [MY-013169] [Server] /usr/sbin/mysqld (mysqld 8.0.15) initializing of server in progress as process 91249
2019-05-31T02:08:03.665256Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: j)n,?QEJu9ju
2019-05-31T02:08:05.810755Z 0 [System] [MY-013170] [Server] /usr/sbin/mysqld (mysqld 8.0.15) initializing of server has completed
2019-05-31T02:08:08.600324Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.15) starting as process 91400
2019-05-31T02:08:12.134663Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.
2019-05-31T02:08:12.221291Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: ‘8.0.15’ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 MySQL Community Server - GPL.
2019-05-31T02:08:12.294986Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Socket: ‘/var/run/mysqld/mysqlx.sock’ bind-address: ‘::’ port: 33060
“j)n,?QEJu9ju”就是初始化的密码（不带前面的空格）
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利用初始化密码登录
mysql -uroot -p初始化密码
修改密码
ALTER user ‘root’@‘localhost’ IDENTIFIED BY ‘Admin@123’
2.关闭密码登录,无密码登录后修改密码
vi /etc/my.cnf
添加skip-grant-tables（添加之后登陆不需要密码）
重启
sevice mysqld start
登陆
直接mysql -uroot -p
Enter
即可登录
登录后修改密码:
ALTER user ‘root’@‘localhost’ IDENTIFIED BY ‘Admin@123’
密码必须复杂,123456是设置不成的
6.开启远程访问
登录mysql
mysql -uroot -p修改后的密码
选择mysql数据库
use mysql
允许远程访问
update user set host = ‘%’ where user = ‘root’;