Expression evaluation error

Hi

I have an interface where I'm displaying data related to a case and that data actually from another source where they provided it as a view. Now since they have emptied the view the expression rule that fetches the data from this view is throwing error as an error occurred while retrieving the data:unexpected error executing query...Can anyone help me in handling this null data. It would be great if anyone can provide an example query expression.

Thanks in advance.