1.官网找到 https://dev.mysql.com/downloads/repo/yum/
2.wget https://repo.mysql.com/mysql80-community-release-el7-3.noarch.rpm
rpm -ivh mysql80-community-release-el7-3.noarch.rpm
若果报错误：warning: mysql80-community-release-el8-1.noarch.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
解决：rpm --import /etc/pki/rpm-gpg/RPM*
重新 rpm -ivh mysql80-community-release-el7-3.noarch.rpm
说明：虽然下载的源文件名字为mysql80-community-release-el7-3.noarch.rpm，不用担心，里边其实是包含了我们所要装的版本
yum repolist all | grep mysql
可以看到，默认的安装源为mysql80-community版本
配置默认源5.7
使用yum-config-manager --disable mysql80-community来取消mysql80-community的默认安装，然后
使用yum-config-manager --enable mysql57-community来使能mysql57-community成为yum默认安装版本。
安装
执行安装命令：
yum install mysql-community-server
yum -y install mysql-devel
启动mysql服务
systemctl restart mysqld.service //重启mysql服务
systemctl status mysqld.service //查看mysql状态
systemctl stop mysqld.service //停止mysql服务
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获取临时密码
临时密码存在/var/log/mysqld.log中，使用如下命令查看：
grep "temporary password" /var/log/mysqld.log
登陆mysql
mysql -u root -p
Enter password:
进入mysql > update user set authentication_string = password('root') where user='root'; 后面跟分号 密码策略：大小写字母+数字+特殊符号
也可忽略验证：
vim /etc/my.cnf
增加
skip-grant-tables 忽略验证 保存，重新运行mysql mysql -u root -p 直接enter 进入不用输入密码
修改用户密码：
update user set authentication_string = password('root') where user='root';
root 登录后
一定要修改密码
alter user 'root'@'localhost' identified by 'test';
然后就可以了。
# For advice on how to change settings please see # http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html [mysqld] #skip-grant-tables # # Remove leading # and set to the amount of RAM for the most important data # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%. # innodb_buffer_pool_size = 128M # # Remove leading # to turn on a very important data integrity option: logging # changes to the binary log between backups. # log_bin # # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M datadir=/data/mysql #socket=/var/lib/mysql/mysql.sock socket=/data/mysql/mysql.sock # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid
更改用户权限增加用户
1.创建新用户的SQL语句：
CREATE USER ‘pig‘@‘192.168.1.101_‘ IDENDIFIED BY ‘123456‘;
// pig 是用户名，@后面的是指定ip(如果不限制只能在某个ip，@后面改为‘%’),by后面的是 密码
2.设置这个用户的权限，使用GRANT语句
(如限制某个用户只能查询，不能修改，或者限定只能查询特定的表)
语法：
mysql> grant 权限1,权限2,...权限n on 数据库名称.表名称 to 用户名@用户地址 identified by ‘连接口令‘;
可选的权限列表：select, insert, update, delete, create, drop,
index, alter, grant, references, reload,
shutdown, process, file等14个权限
eg:
1. mysql> grant select,insert,update,delete,create,drop on vtdc.employee to joe@10.163.225.87 identified by ‘123‘;
给来自10.163.225.87的用户joe分配可对数据库vtdc的employee表
进行select,insert,update,delete,create,drop等操作的权限，并设定口令为123。
2. mysql>grant all privileges on vtdc.* to joe@10.163.225.87 identified by ‘123‘;
给来自10.163.225.87的用户joe分配可对数据库vtdc所有表进行所有操作的权限，并设定口令为123。
3. mysql>grant all privileges on *.* to joe@10.163.225.87 identified by ‘123‘;
给来自10.163.225.87的用户joe分配可对所有数据库的所有表进行所有操作的权限，并设定口令为123。
4. mysql>grant all privileges on *.* to joe@localhost identified by ‘123‘;
给本机用户joe分配可对所有数据库的所有表进行所有操作的权限，并设定口令为123。
5. mysql>flush privileges; //刷新系统权限表
use mysql
show databases;(显示db)
show tables;显示表
describe test; 或者show columns from test；显示表结构
drop table test;删除表
create table test( id int not null auto_increment primary key, title varchar(100) not null, name varchar(50) not null, age int not null, createtime datetime not null); 创建表
insert into test(title,name,age,createtime) values ('11','222',11,'2021-09-09'); 添加数据
update test set title='876868' where id =1; 修改数据
delete from test where id=1; 删除数据
select * from test order by id asc; 排序