ผู้ป่วยโรคหลักคือโรคหลอดเลือดหัวใจและจำนวนวันที่ต้องพักรักษาตัวในโรงพยาบาลมากกว่า 3 จำนวนเท่าใด ไม่จำเป็นต้องใช้ตารางทั้งหมด
what is the number of patients whose primary disease is coronary artery disease and days of hospital stay is greater than 3?It is not neccessary to use all the tables.
 demographic:  subject_id [ text]  hadm_id [ text]  name [ text]  marital_status [ text]  age [ text]  dob [ text]  gender [ text]  language [ text]  religion [ text]  admission_type [ text]  days_stay [ text]  insurance [ text]  ethnicity [ text]  expire_flag [ text]  admission_location [ text]  discharge_location [ text]  diagnosis [ text]  dod [ text]  dob_year [ text]  dod_year [ text]  admittime [ text]  dischtime [ text]  admityear [ text] 
SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic WHERE demographic.diagnosis = "CORONARY ARTERY DISEASE" AND demographic.days_stay > "3"