How do I “orderby” a column without losing posts that don’t have the column?

I’m currently using the following code to sort and order my super awesome column that I created:

This code gets the job done, but when I click on the column header in order to sort the column, any posts that don’t contain that meta field are not included in the listing of posts. I would like to have it such that any posts that don’t contain the meta field evaluate as and are sorted as zeroes. How can I accomplish this? Thanks.