ขอ sao2 ขั้นต่ำรายปีของผู้ป่วย 027-135249 จนถึง 4 เดือนที่แล้ว ไม่จำเป็นต้องใช้ตารางทั้งหมด
give me patient 027-135249's yearly minimum sao2 until 4 months ago.It is not neccessary to use all the tables.
 vitalperiodic:  vitalperiodicid [ number]  patientunitstayid [ number]  temperature [ number]  sao2 [ number]  heartrate [ number]  respiration [ number]  systemicsystolic [ number]  systemicdiastolic [ number]  systemicmean [ number]  observationtime [ time] 
SELECT MIN(vitalperiodic.sao2) FROM vitalperiodic WHERE vitalperiodic.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '027-135249')) AND NOT vitalperiodic.sao2 IS NULL AND DATETIME(vitalperiodic.observationtime) <= DATETIME(CURRENT_TIME(), '-4 month') GROUP BY STRFTIME('%y', vitalperiodic.observationtime)