oracle函数中游标的使用

function test(in_type in varchar2) return varchar2 is
    cursor v_rules is
      select s.id,,
      from student s;
    v_rule v_rules%rowtype;
    v_id varchar2(16);
    v_name varchar2(4000);
  begin
    for v_rule in v_rules loop
      v_id := v_rule.id;
      v_name := v_rule.name;
    end loop; 
  end;