linux安装mysql

1.下载mysql
https://dev.mysql.com/downloads/mysql/
操作系统选RedHat
依次下载四个安装包
mysql-community-common-5.7.33-1.el7.x86_64.rpm
mysql-community-libs-5.7.33-1.el7.x86_64.rpm
mysql-community-server-5.7.33-1.el7.x86_64.rpm
mysql-community-client-5.7.33-1.el7.x86_64.rpm

2.移除已安装mysql，mariadb
centos7默认安装mariadb
rpm查看是否安装过mysql：
rpm -qa|grep -i mysql
rpm -qa|grep -i mariadb

移除安装过的mariadb和mysql
rpm -e --nodeps mariadb-libs-5.5.60-1.el7_5.x86_64

whereis mysql
find / -name mysql

rm -rf 删除
查看mysql是否启动：ps -ef |grep mysql

3.Xshell使用rz命令上传msyql文件并安装
下载地址：https://dev.mysql.com/downloads/mysql/
mysql-community-common-5.7.33-1.el7.x86_64.rpm
mysql-community-libs-5.7.33-1.el7.x86_64.rpm
mysql-community-client-5.7.33-1.el7.x86_64.rpm
mysql-community-server-5.7.33-1.el7.x86_64.rpm
如下命令依次安装以上4个文件
rpm -ivh mysql-community-common-5.7.33-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.33-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.33-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.33-1.el7.x86_64.rp

4.启动mysql
service mysqld start
systemctl start mysqld.service

5.连接msyql失败问题
mysql -uroot -p
登录失败：ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
解决办法：
vim /etc/my.cnf
[mysqld]添加skip-grant-tables，这样再次登陆就不用输入密码，直接回车就进入数据库了。
重启服务：service mysqld restart
连接mysql：mysql -uroot -p
输入密码直接回车，进入mysql

6.设置数据库密码
use mysql;
show tables;
查看user表结构：desc user;
Host存的是允许访问的主机
User是登录名
authentication_string是登录密码，老版本用的字段是password
修改密码：update user set authentication_string=password('123456') where user='root';
退出mysql：quit;
重启服务：service mysqld restart