create or alter procedure VER_EDAD (
    N_EDAD numeric(15,4),
    SEPARADOR varchar(1),
    CORTO char(1))
returns (
    C_EDAD varchar(8))
as
begin
  /* Procedure Text */
  if (separador is null) then
    separador = ' ';
  if (corto is null) then
    corto = 'N';

  c_edad =
    CASE
      when :n_edad > 1 then
        cast(cast(:n_edad as integer) as varchar(3))||separador||iif(upper(corto)='N','Años', 'A')
     when :n_edad = 1  then
        cast(cast(:n_edad as integer) as varchar(3))||separador||iif(upper(corto)='N','Año', 'A')
     when :n_edad > 0.01 then
        cast(cast(:n_edad*100 as integer) as varchar(3))||separador||iif(upper(corto)='N','Meses', 'M')
     when :n_edad = 0.01 then
        cast(cast(:n_edad*100 as integer) as varchar(3))||separador||iif(upper(corto)='N','Mes', 'M')
     when :n_edad > 0.0001 then
        cast(cast(:n_edad*10000 as integer) as varchar(3))||separador||iif(upper(corto)='N','Días', 'D')
     when :n_edad = 0.0001 then
       cast(cast(:n_edad*10000 as integer) as varchar(3))||separador||iif(upper(corto)='N','Día', 'D')
     when :n_edad = 0 then
       'RN'
    end;

  suspend;
end

Thank you very much to all