instruction: what is the minimum value of ionized calcium of patient 006-251537 in 06/2104?
response: SELECT MIN(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 = '006-251537')) AND lab.labname = 'ionized calcium' AND STRFTIME('%y-%m', lab.labresulttime) = '2104-06'