นับจำนวนคนไข้ 25523 ที่เข้าห้อง ICU ปี 2103 ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
count how many times patient 25523 has been to the intensive care unit in 2103.It is not neccessary to use all the tables.
 patients:  row_id [ number]  subject_id [ number]  gender [ text]  dob [ time]  dod [ time] 
SELECT COUNT(DISTINCT icustays.icustay_id) FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 25523) AND STRFTIME('%y', icustays.intime) = '2103'