SQL删除完全重复数据

with a  as (select pn ,row_number()over(partition by pn order by pn) row_num from dianlu_bak_160115)

--select pn,COUNT(1),max(row_num) maxr,MIN(row_num) minr from a group by pn having COUNT(1)>1

delete a where row_num<>1;