instruction: give me the difference between the total amount of input and the output for patient 21468 on 03/25/this year.
response: SELECT (SELECT SUM(inputevents_cv.amount) FROM inputevents_cv WHERE inputevents_cv.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 21468)) AND DATETIME(inputevents_cv.charttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year') AND STRFTIME('%m-%d', inputevents_cv.charttime) = '03-25') - (SELECT SUM(outputevents.value) FROM outputevents WHERE outputevents.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 21468)) AND DATETIME(outputevents.charttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year') AND STRFTIME('%m-%d', outputevents.charttime) = '03-25')