# echo "deb http://repo.mysql.com/apt/debian/ $(lsb_release -sc) mysql-5.6" >> /etc/apt/sources.list && echo "deb-src http://repo.mysql.com/apt/debian/ $(lsb_release -sc) mysql-5.6" >> /etc/apt/sources.list && apt-get update

# apt-get install mysql-server-5.6
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package mysql-server-5.6 is a virtual package provided by:
  mysql-community-server 5.6.29-1debian8 [Not candidate version]

E: Package 'mysql-server-5.6' has no installation candidate