instruction: how many medication patient 006-21388 has been prescribed during a year before?
response: SELECT COUNT(*) FROM medication WHERE medication.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '006-21388')) AND DATETIME(medication.drugstarttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-1 year')