A hospital stores the names of patients and doctors in the following table:
TABLE patients id INTEGER NOT NULL PRIMARY KEY patient VARCHAR(100) doctor VARCHAR(100) NOT NULL
The hospital refers to a patient whose name is unknown as 'John Doe'. These patients are represented as null in the patients table.
Which of the following queries can be used to select a list of patients ('John Doe' if patient is null) and their doctors?
(multiple correct answers possible)