CREATE TABLE patient (name VARCHAR, ssn VARCHAR)
CREATE TABLE appointment (patient VARCHAR, start VARCHAR)

What is the name of the patient who made the most recent appointment?
SELECT T1.name FROM patient AS T1 JOIN appointment AS T2 ON T1.ssn = T2.patient ORDER BY T2.start DESC LIMIT 1
SELECT "T1"."name" FROM "patient" AS "T1" JOIN "appointment" AS "T2" ON "T1"."ssn" = "T2"."patient" ORDER BY "T2"."start" DESC NULLS LAST LIMIT 1