為什麼我第一次呼叫下面這個function時會傳回正確的值，
  但第二次呼叫時，卻出現EoleException with message 
  'Either BOF or EOF is True, or the current record has
   been deleted. Requested operation requires a current
   record
   
  function getsuplid(a: integer): integer;
  begin
    result:= 0;
    adoquery3.Close;
    adoquery3.SQL.Clear;
    adoquery3.SQL.Add('select cusp_cusp_id from custsupy where cusp_cmpy_id = a');
    doquery3.Open;
    adoquery3.First;
    while not adoquery3.Eof do begin
      result:= adoquery3.Fields.Fields[0].AsInteger;
      adoquery3.next;
    end;
  end;    

function getsuplid(a: integer): integer;
begin
  result:= 0;
  adoquery3.Close;
  adoquery3.SQL.Clear;
  adoquery3.SQL.Add('select cusp_cusp_id from custsupy where cusp_cmpy_id = a');
  doquery3.Open;
  if doquery3.RecordCount > 0 then begin 
    adoquery3.First;
    while not adoquery3.Eof do begin
        result:= adoquery3.Fields.Fields[0].AsInteger;
        adoquery3.next;
      end;
    end;
  end;
end;