卸载Mysql

1.快速删除

yum remove  mysql mysql-server mysql-libs mysql-server

2.查找残留程序

rpm -qa | grep mysql

rpm -qa | grep mariadb

3.删除残留程序

rpm -e --nodeps mariadb-libs-5.5.68-1.el7.x86_64

4.查找残留目录

whereis mysql

5.逐条删除目录

rm –rf /usr/local/mysql

安装Mysql

1.先创建要解压到的目录

mkdir /usr/local/mysql

2.随后解压

tar -zxvf mysql-5.7.25-1.el7.x86_64.rpm-bundle.tar.gz -C /usr/local/mysql

3.按顺序安装rpm包

rpm -ivh mysql-community-common-5.7.25-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.25-1.el7.x86_64.rpm
rpm -ivh mysql-community-devel-5.7.25-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-compat-5.7.25-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.25-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.25-1.el7.x86_64.rpm

启动mysql

1.查看MySQL服务状态

systemctl status mysqld

2.停止Mysql服务

systemctl stop mysqld.service

3.启动MySQL服务

systemctl start mysqld

查看已经启动的服务

netstat -tunlp

netstat -tunlp | grep mysql

4.查看MySQL进程

ps -df | grep mysql

5.设置开机时自动启动MySQL服务，避免每次开机都要启动MySQL

systemctl enable mysqld

登录MySqL

1.查看日志内容中包含password的行信息

cat /var/log/mysqld.log |grep 'A temporary password is generated'

2.根据查询到的密码来登录MySQL

mysql -uroot -p

3.登录成功之后修改密码

  • 设置密码长度最低位数

    set global validate_password_length=4;

  • 设置密码安全等级低，便于密码可修改为root

    set global validate_password_policy=LOW;

  • 设置密码为root

    set password = password('root');

  • 开启访问权限

    grant all on *.* to 'root'@'%' identified by 'root';

  • 刷新权限

    flush privileges;

4.重启Mysql

service mysqld restart

设置Mysql允许远程连接

1.设置防火墙，允许3306端口通过

2.登录mysql

mysql -u root -p

3.查看mysql库中的user表的host字段

use mysql;
select user,host from user;

4.修改root用户的host字段

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

5.使本次修改立即生效

flush privileges;

查看当前数据库内容

1.登录mysql

mysql -u root -p

2.显示所有的数据库

show databases;

3.选择数据库

use xxx;

4.显示表

show tables;

5.直接查询语句，显示表数据

select * from tbl;

6.导入sql脚本

# 选择
mysql>use abc;
# 编码
mysql>set names utf8;
# 导入
mysql>source /usr/abcs.sql;