what is the four most common lab testing done since 5 years ago?
select d_labitems.label from d_labitems where d_labitems.itemid in ( select t1.itemid from ( select labevents.itemid, dense_rank() over ( order by count(*) desc ) as c1 from labevents where datetime(labevents.charttime) >= datetime(current_time,'-5 year') group by labevents.itemid ) as t1 where t1.c1 <= 4 )