无法添加两个时间变量

I'm trying to add 1 day on to a date selected from my database so I can compare dates later. The problem is that the two are not adding, I always get the value from my table, not the added one.

$busca_query = mysql_query("SELECT status, ban_time, desde, login FROM account.account WHERE status='BAN' AND ban_time = '1 Dia';") or die(mysql_error());
$row = mysql_fetch_row($busca_query);
$result = $row['1'];
$desde = $row['2'];
$login = $row['3'];
$dia = '0000-00-01 00:00:00';
$data_desban = strtotime($desde)+strtotime($dia);
echo date("Y-m-d H:i:s", $data_desban);

The date from my table is like this:

2015-05-28 17:18:38

and the date I get its the same, 2015-05-28 17:18:38

Just add a day like this:

$data_desban = strtotime($desde.' + 1 day');
echo date("Y-m-d H:i:s", $data_desban);

Another option, since it looks like your query may return multiple rows, is to do the calculation in the query instead:

SELECT status, ban_time, desde, login, 
    DATE_ADD(desde, INTERVAL 1 DAY) as data_desban
FROM account.account 
WHERE status='BAN' AND ban_time = '1 Dia';

'0000-00-01 00:00:00' is well outside the range of 32-bit unix timestamps, and wouldn't be a valid date even then: Why not use DateTime objects instead?

$dia = 'P1D';
$data_desban = new DateTime($desde);
$data_desban->add(new DateInterval($dia));
echo $data_desban->format("Y-m-d H:i:s");