What is the zip postcode where staff named Janessa Sawayn lived? | Do you mean the zip code of staff with first name Janessa and last name Sawayn lived? | Yes
SELECT T1.zip_postcode FROM Addresses AS T1 JOIN Staff AS T2 ON T1.address_id  =  T2.staff_address_id WHERE T2.first_name  =  "Janessa" AND T2.last_name  =  "Sawayn"
zip postcode where staff lived refers to zip_postcode from Addresses table; staff named Janessa Sawayn refers to condition WHERE first_name = 'Janessa' AND last_name = 'Sawayn'; joining Addresses and Staff tables on address_id and staff_address_id.