MySql安装

1、下载mysql安装包

再mysql官方下载安装包

2、删除依赖包

# 查找依赖包
rpm -qa | grep mysql
rpm -qa | grep MySQL
rpm -qa | grep mariadb

# 删除查询到的依赖包
rpm -e  --nodeps mariadb-libs-5.5.68-1.el7.x86_64

3、安装mysql

# 将安装包上传到linux中
# mysql-community-client-5.7.37-1.el7.x86_64.rpm
# mysql-community-common-5.7.37-1.el7.x86_64.rpm
# mysql-community-libs-5.7.37-1.el7.x86_64.rpm
# mysql-community-server-5.7.37-1.el7.x86_64.rpm

# 安装mysql
rpm -ivh mysql-community-common-5.7.37-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.37-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.37-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.37-1.el7.x86_64.rpm


# 如果安装过程中出现缺少依赖，将依赖安装以下
# yum -y install autoconf
# yum -y install net-tools

4、启动mysql

systemctl start mysqld


# 插入状态 
systemctl status mysqld

5、修改mysql登录密码

# 获取临时密码
grep 'temporary password' /var/log/mysqld.log

# 通过临时密码登录mysql
mysql -uroot -p

# 修改密码的安全策略
set global validate_password_policy=0;
set global validate_password_length=4;

# 修改密码
set password = password('123456');

# 刷新权限
flush privileges;

# 退出
exit

7、使用

-- 1、登录数据库
mysql -uroot -p123456

-- 2、创建数据库 -- DDL
create database bigdata default charset utf8;

-- 3、列出所有的数据库
show databases;

-- 4、切换数据库
use bigdata;

-- 5、创建表 -- DDL
create table students(
    id varchar(255),
    name varchar(255),
    age int,
    sex varchar(255),
    clazz varchar(255)
);


-- 6、使用sql导入数据到表中
LOAD DATA local  INFILE '/root/student.txt' INTO TABLE students FIELDS TERMINATED BY ',' ;

--7、使用sql查询数据
-- 1、查询文科一班的学生
select * from students where name='范念薇';

-- 2、统计每个班级的人数
select 
clazz,count(1) as num 
from students
group by clazz;

Mysql卸载

1、停止mysql服务

systemctl stop mysqld

2、删除依赖包

rpm -qa |grep -i mysql

yum remove mysql-community mysql-community-server mysql-community-libs mysql-community-common

3、删除mysql文件

# 查找和mysql相关的所有的文件
find / -name mysql

# 删除以下目录
/etc/logrotate.d/mysql
/etc/selinux/targeted/active/modules/100/mysql
/var/lib/mysql  # mysql保存数据的位置
/var/lib/mysql/mysql
/usr/bin/mysql
/usr/lib64/mysql
/usr/share/mysql