count the number of times patient 23858 has been given a tpn d15.0 until 75 months ago.
select count(*) 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 = 23858 ) ) and inputevents_cv.itemid in ( select d_items.itemid from d_items where d_items.label = 'tpn d15.0' and d_items.linksto = 'inputevents_cv' ) and datetime(inputevents_cv.charttime) <= datetime(current_time,'-75 month')