apt-get mysql 5.7 code example
Example: install mysql 5.7 ubuntu 20.04
sudo apt install -f mysql-client=5.7.32-1ubuntu18.04 mysql-community-server=5.7.32-1ubuntu18.04 mysql-server=5.7.32-1ubuntu18.04
sudo apt install -f mysql-client=5.7.32-1ubuntu18.04 mysql-community-server=5.7.32-1ubuntu18.04 mysql-server=5.7.32-1ubuntu18.04