create or replace function to_number_force(input in varchar2) return number
is
	a varchar2(2000);
	b char(1);
	x number := 1;
begin
	a := ltrim(rtrim(input));
	b := substr(a, 1, 1);
	if(b = '+' or b = '-') then
		x := 2;
	end if;
	while x <= length(a) loop
		b := substr(a, x, 1);
		if(b not in ('0','1','2','3','4','5','6','7','8','9','.')) then
			return NULL;
		end if;
		x := x + 1;
	end loop;
	return to_number(c);
end;
/