instruction: how much of a change in patient 017-70504's bun is taking place measured at 2103-04-13 06:49:00 compared to the value measured at 2103-04-12 10:02:00?
response: SELECT (SELECT 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 = '017-70504')) AND lab.labname = 'bun' AND lab.labresulttime = '2103-04-13 06:49:00') - (SELECT 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 = '017-70504')) AND lab.labname = 'bun' AND lab.labresulttime = '2103-04-12 10:02:00')