what is the difference between the hematocrit of patient 1232 measured at 2102-04-11 05:25:00 compared to the value measured at 2102-04-08 23:25:00?
select ( select labevents.valuenum from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 1232 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'hematocrit' ) and labevents.charttime = '2102-04-11 05:25:00' ) - ( select labevents.valuenum from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 1232 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'hematocrit' ) and labevents.charttime = '2102-04-08 23:25:00' )