when did patient 17237 have a minimum arterial bp mean for the first time on 05/15/2104?
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 = 17237 ) ) and chartevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'arterial bp mean' and d_items.linksto = 'chartevents' ) and strftime('%y-%m-%d',chartevents.charttime) = '2104-05-15' order by chartevents.valuenum asc, chartevents.charttime asc limit 1