Table schema:
CREATE TABLE patient (SSN VARCHAR); CREATE TABLE prescribes (patient VARCHAR, physician VARCHAR); CREATE TABLE physician (employeeid VARCHAR, name VARCHAR)

Question: 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"