ผู้ป่วย 9294 ได้รับแมกนีเซียมขั้นต่ำครั้งสุดท้ายเมื่อใดในการมาโรงพยาบาลครั้งแรก? ไม่จำเป็นที่จะต้องใช้โต๊ะทั้งหมด
when did patient 9294 last have minimum magnesium on their first hospital visit?It is not neccessary to use all the tables.
 icustays:  row_id [ number]  subject_id [ number]  hadm_id [ number]  icustay_id [ number]  first_careunit [ text]  last_careunit [ text]  first_wardid [ number]  last_wardid [ number]  intime [ time]  outtime [ time] 
SELECT labevents.charttime FROM labevents WHERE labevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 9294 AND NOT admissions.dischtime IS NULL ORDER BY admissions.admittime LIMIT 1) AND labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'magnesium') ORDER BY labevents.valuenum, labevents.charttime DESC LIMIT 1