create or replace package p_view_param is
  function set_param(num varchar2) return number;
  function get_param return varchar2;
end p_view_param;

create or replace package body p_view_param is
  paramValue varchar2(4000);
  function set_param(num varchar2) return number is
  begin
    paramValue := num;
    return 0;
  end;

  function get_param return varchar2 is
  begin
    return paramValue;
  end;
end p_view_param;

视图中获取参数
create or replace view viewname as
select * from tablename where aa=p_view_param.get_param();

调用时如下
select * from viewname where p_view_param.set_param('dd')=0

?