如何获取2014-11-12三天前的日期

$time='2014-11-12';
echo date('Y-m-d',strtotime("$time-3 days"));
?>

$conn=mysqli_connect('localhost','root','root');
$res=mysqli_query($conn,"SELECT ADDDATE('2014-11-12',INTERVAL -3 DAY)");
$row=mysqli_fetch_array($res);
echo $row[0];

2014-11-09