Query whether meta value is not null, and then whether is null

I’m working on displaying a list of custom post types (e.g Stores) titles on a page. Each Store has a custom meta value option for a phone number.

Is there a way to query whether or not the custom meta for phone is null (or not null)? I would like to display Stores with phone numbers first, then display the list of stores without phone numbers after (so I can style them differently).

Any ideas?