when did patient 97314 get prescribed a drug via iv for the last time until 3 months ago?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 97314 ) and prescriptions.route = 'iv' and datetime(prescriptions.startdate) <= datetime(current_time,'-3 month') order by prescriptions.startdate desc limit 1