Install Microsoft SQL Server

Import the public repository GPG keys:

wget -qO- https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -

Register the Microsoft SQL Server Ubuntu repository for SQL Server

sudo add-apt-repository "$(wget -qO- https://packages.microsoft.com/config/ubuntu/18.04/mssql-server-2019.list)"

Install MSSQL Server:

sudo apt update
sudo apt install -y mssql-server

Complete the setup, SA password and choose version:

sudo /opt/mssql/bin/mssql-conf setup

Check that it is running:

systemctl status mssql-server --no-pager

MSSQL runs on port 1433 by default, so make sure that is open on the firewall and test the connection.

If trying to connect to the instance using SQL Server Management Studio, you may need to edit the Connection Properties section and select Encrypt Connection and Trust Server Certificate.