1. 首先输入mysql --version看有没有安装过其他版本的mysql，有的话卸载掉

apt-get remove mysql-common
apt-get remove mysql*

2. 下载包并解压升级

下载地址：https://repo.mysql.com//mysql-apt-config_0.8.10-1_all.deb

sudo dpkg -i mysql-apt-config_0.8.9-1_all.deb 
sudo apt-get update

若更新过程中出现错误：EXPKEYSIG 8C718D3B5072E1F5 MySQL Release Engineering

执行以下操作再次更新就OK

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8C718D3B5072E1F5
sudo apt-get update

3. 安装mysql

sudo apt-get install mysql-server mysql-common

若是报如下错：

换成下面源（vi /etc/apt/sources.list），然后再apt-get update

deb http://mirrors.aliyun.com/debian/ stretch main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ stretch main non-free contrib
deb http://mirrors.aliyun.com/debian-security stretch/updates main
deb-src http://mirrors.aliyun.com/debian-security stretch/updates main
deb http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib
deb http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib

再次执行安装 sudo apt-get install mysql-server mysql-common

4. 启动mysql5.7

service mysql start

5. 添加访问权限

vi /etc/mysql/mysql.conf.d/mysqld.cnf

bind-address = 0.0.0.0