count the number of times that patient 30733 had received a eosinophils test during the previous year?
select count(*) from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'eosinophils' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 30733 ) and datetime(labevents.charttime,'start of year') = datetime(current_time,'start of year','-1 year')