instruction: so what's the average bicarbonate value of patient 006-207754 until 17 months ago?
response: SELECT AVG(lab.labresult) FROM lab WHERE lab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '006-207754')) AND lab.labname = 'bicarbonate' AND DATETIME(lab.labresulttime) <= DATETIME(CURRENT_TIME(), '-17 month')