CREATE TABLE patient (SSN VARCHAR(255)); CREATE TABLE prescribes (patient VARCHAR(255), physician VARCHAR(255)); CREATE TABLE physician (employeeid VARCHAR(255), name VARCHAR(255))
How many patients' prescriptions are made by physician John Dorian?
    
SQL: SELECT COUNT(T1.SSN) FROM patient AS T1 JOIN prescribes AS T2 ON T1.SSN = T2.patient JOIN physician AS T3 ON T2.physician = T3.employeeid WHERE T3.name = "John Dorian"