นับจำนวนผู้ป่วยอายุต่ำกว่า 67 ปี ที่มีอาการปวดท้อง โรคปฐมภูมิ ไม่จำเป็นต้องใช้ทุกตาราง
count the number of patients under 67 years of age who have abdominal pain primary disease.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 = "ABDOMINAL PAIN" AND demographic.age < "67"