นับจำนวนผู้ป่วยที่อายุเข้ารักษาน้อยกว่า 2,157 ปี และวินิจฉัยชื่อสั้นว่าเป็นโรคหลอดเลือดหัวใจตีบหรือไม่ ไม่จำเป็นต้องใช้ทุกตาราง
count the number of patients whose admission year is less than 2157 and diagnoses short title is intermed coronary synd?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 INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id WHERE demographic.admityear < "2157" AND diagnoses.short_title = "Intermed coronary synd"