CREATE TABLE physician (employeeid VARCHAR2, name VARCHAR2)
CREATE TABLE patient (SSN VARCHAR2)
CREATE TABLE prescribes (patient VARCHAR2, physician VARCHAR2)

How many patients' prescriptions are made by physician John Dorian?
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"
SELECT COUNT("T1"."SSN") FROM "patient" "T1" JOIN "prescribes" "T2" ON "T1"."SSN" = "T2"."patient" JOIN "physician" "T3" ON "John Dorian" = "T3"."name" AND "T2"."physician" = "T3"."employeeid"