count the number of times patient 4288 had been prescribed azathioprine sodium since 1 year ago?
select count(*) from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 4288 ) and prescriptions.drug = 'azathioprine sodium' and datetime(prescriptions.startdate) >= datetime(current_time,'-1 year')