instruction: indicate the daily minimum amount of sao2 for patient 027-111412 in 08/2105.
response: 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 = '027-111412')) AND NOT vitalperiodic.sao2 IS NULL AND STRFTIME('%y-%m', vitalperiodic.observationtime) = '2105-08' GROUP BY STRFTIME('%y-%m-%d', vitalperiodic.observationtime)