SQL query returns no rows error

I have an SQL query that in certain circumstances will contain no information. I currently get the SQL query returns no rows error. What would be a proper way to fix this?

Thanks and have a great day.

SELECT firstname + ' ' + Lastname FROM employeedate WHERE mach_num = {dynamic data} AND operator = {dynamic data} 

Thats what the “fallback value” is for on the SQL query binding.