what I would do is find a mysql-to-unixtimestamp function like below (or just use this one):
function mysql_timestamp_to_timestamp($dt)
{
$yr=strval(substr($dt,0,4));
$mo=strval(substr($dt,4,2));
$da=strval(substr($dt,6,2));
$hr=strval(substr($dt,8,2));
$mi=strval(substr($dt,10,2));
$se=strval(substr($dt,10,2));
return mktime($hr,$mi,$se,$mo,$da,$yr);
}
when you get your date from mysql, send it to this function. It will then be a unix timestamp when it comes out. Once you get the timestamp, you can use mktime() to add 10 days to that timestamp. Or if you are not pulling the value from mysql, you can just use mktime() in the first place and add 10 days to it. hope this helps.