Cómo seleccionar una fila máxima para cada grupo en SQL

intente esta consulta en su lugar,

  WITH OrderedOrders AS
  (
     SELECT country,grpid,value,ROW_NUMBER() OVER(PARTITION BY country ORDER BY   country,value DESC) AS 'RowNumber' 
     FROM test1
  ) 
 select * from  OrderedOrders
 where RowNumber =1