related record returns element when empty

Hi,

If a relation does not meet the conditions for getting data, should the output return empty? Example..

The database query returns empty

The queryRecordType returns a value

This is correct?
How can I get an empty value, like in a database?

This is a modification of lesson 4 exercise 2, in the associate course certificate. (If I don´t write the "fields: AA Vehicle.maintenance.cost", the output is the same, removing maintenance list)

Thanks for the help