during this month patient 15794 had been prescribed d5w?
select count(*)>0 from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 15794 ) and prescriptions.drug = 'd5w' and datetime(prescriptions.startdate,'start of month') = datetime(current_time,'start of month','-0 month')