คำนวณจำนวนผู้ป่วยที่เข้าพักในหน่วยดูแลไมคิวในปีที่ผ่านมา ไม่จำเป็นต้องใช้ตารางทั้งหมด
calculate the number of patients who have stayed in the micu careunit during the last year.It is not neccessary to use all the tables.
 outputevents:  row_id [ number]  subject_id [ number]  hadm_id [ number]  icustay_id [ number]  charttime [ time]  itemid [ number]  value [ number] 
SELECT COUNT(DISTINCT admissions.subject_id) FROM admissions WHERE admissions.hadm_id IN (SELECT transfers.hadm_id FROM transfers WHERE transfers.careunit = 'micu' AND DATETIME(transfers.intime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-1 year'))