when was the last hospital admission that patient 17694 was admitted since 3 years ago via the transfer from hosp/extram?
select admissions.admittime from admissions where admissions.subject_id = 17694 and admissions.admission_location = 'transfer from hosp/extram' and datetime(admissions.admittime) >= datetime(current_time,'-3 year') order by admissions.admittime desc limit 1