count the number of times patient 97330 had had a dialysis output on the current hospital visit.
select count(*) 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 = 97330 and admissions.dischtime is null ) ) and outputevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'dialysis output' and d_items.linksto = 'outputevents' )