Can you show me the name of the patient who stays in room 111?
SELECT T2.name FROM stay AS T1 JOIN patient AS T2 ON T1.Patient  =  T2.SSN JOIN Prescribes AS T3 ON T3.Patient  =  T2.SSN JOIN Medication AS T4 ON T3.Medication  =  T4.Code WHERE room  =  111
name of the patient refers to T2.name; patient stays in room 111 refers to room = 111; need to join tables stay, patient, and prescribes based on Patient = SSN and join with Medication on Medication = Code to get the required information.