calculate how many times patient 52736 has received a base excess laboratory test the previous year.
select count(*) from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'base excess' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 52736 ) and datetime(labevents.charttime,'start of year') = datetime(current_time,'start of year','-1 year')