what's the minimum total cost of a hospital, including cholesterol ratio (total/hdl) lab tests since 1 year 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 = 'cholesterol ratio (total/hdl)' ) ) and datetime(cost.chargetime) >= datetime(current_time,'-1 year') group by cost.hadm_id ) as t1