อายุขั้นต่ำของผู้ป่วยที่รักษาตัวในโรงพยาบาลคือ 20 ปี และปีที่เสียชีวิตน้อยกว่า 2164 คือเท่าใด ไม่จำเป็นต้องใช้ตารางทั้งหมด
what is minimum age of patients whose days of hospital stay is 20 and year of death is less than 2164?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 MIN(demographic.age) FROM demographic WHERE demographic.days_stay = "20" AND demographic.dod_year < "2164.0"