what is the minimum amount of hospital cost which includes a cd8 cells, percent testing lab test until 2 years ago?
select min(t1.c1) from ( select sum(cost.cost) as c1 from cost where cost.hadm_id in ( select labevents.hadm_id from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'cd8 cells, percent' ) ) and datetime(cost.chargetime) <= datetime(current_time,'-2 year') group by cost.hadm_id ) as t1