sql 列有相同内容时，只保留一个

SQL语句查询出来的第一张图，我想让他按第二个图显示要怎么实现．
SQL语句要怎么写，请帮忙，万分感谢！

select if(rn!=1,'',gw ) as gw , t if(rn!=1,'',nw )  as nw ,dimensio  from (
select  gw , nw ，dimensio ,row_number() over(partition by gw , nw ，dimensio order by  1 )  as rn from  table_name 
) a