ครั้งสุดท้ายที่ผู้ป่วย 1902 มีปริมาณไบคาร์บอเนตขั้นต่ำนับตั้งแต่ 47 เดือนที่แล้วคือเมื่อใด?ไม่จำเป็นต้องใช้ตารางทั้งหมด
when was the last time that patient 1902 has the minimum bicarbonate since 47 months ago?It is not neccessary to use all the tables.
 admissions:  row_id [ number]  subject_id [ number]  hadm_id [ number]  admittime [ time]  dischtime [ time]  admission_type [ text]  admission_location [ text]  discharge_location [ text]  insurance [ text]  language [ text]  marital_status [ text]  ethnicity [ text]  age [ number] 
SELECT labevents.charttime FROM labevents WHERE labevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 1902) AND labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'bicarbonate') AND DATETIME(labevents.charttime) >= DATETIME(CURRENT_TIME(), '-47 month') ORDER BY labevents.valuenum, labevents.charttime DESC LIMIT 1