มีผู้ป่วยอยู่ในหน่วยดูแล csru กี่คน?ไม่จำเป็นต้องใช้ตารางทั้งหมด
what number of patients are staying in the csru careunit?It is not neccessary to use all the tables.
 labevents:  row_id [ number]  subject_id [ number]  hadm_id [ number]  itemid [ number]  charttime [ time]  valuenum [ number]  valueuom [ text] 
SELECT COUNT(DISTINCT admissions.subject_id) FROM admissions WHERE admissions.hadm_id IN (SELECT transfers.hadm_id FROM transfers WHERE transfers.careunit = 'csru')