คนไข้ที่อายุน้อยกว่า 49 ปี และชื่อย่อของการรักษาคือ clo endosc bx bile duct มีจำนวนเท่าใด ไม่จำเป็นต้องใช้ตารางทั้งหมด
what is the number of patients whose age is less than 49 and procedure short title is clo endosc bx bile duct?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 procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.age < "49" AND procedures.short_title = "Clo endosc bx bile duct"