insert into table zs.dw_pvs_refhost_topn_h partition(datestr=’2016-03-18’)
select t.hour,t.od,t.ref_host,t.ref_host_cnts from
(select ref_host,ref_host_cnts,concat(month,day,hour) as hour,
row_number() over (partition by concat(month,day,hour) order by ref_host_cnts desc) as od
from zs.dw_ref_host_visit_cnts_h) t where od<=3;