ครั้งแรกที่มีการวัด/ถ่าย bp ของหลอดเลือดแดง [ซิสโตลิก] ของผู้ป่วย 21079 คือเมื่อใด?ไม่จำเป็นต้องใช้ตารางทั้งหมด
when was the first time that the arterial bp [systolic] of patient 21079 was measured / taken?It is not neccessary to use all the tables.
 microbiologyevents:  row_id [ number]  subject_id [ number]  hadm_id [ number]  charttime [ time]  spec_type_desc [ text]  org_name [ text] 
SELECT chartevents.charttime FROM chartevents WHERE chartevents.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 21079)) AND chartevents.itemid IN (SELECT d_items.itemid FROM d_items WHERE d_items.label = 'arterial bp [systolic]' AND d_items.linksto = 'chartevents') ORDER BY chartevents.charttime LIMIT 1