Or, if you'd rather use POSIX:

my $offset = 65;
my $date = strftime "%Y-%m-%d",
    localtime(time - $offset * 86400);
[download]

And if you'd rather have the format for a datetime field:

my $datetime = strftime "%Y-%m-%d %H:%M:%S",
    localtime(time - $offset * 86400);
[download]

In fact, MySQL itself has some date/time functions that do a lot of the formatting for you, so you could use those instead. The FROM_UNIXTIME function takes a Unix timestamp (epoch seconds) and turns it into a MySQL datetime format for you:

my $offset = 65;
my $time = $offset * 86400;

my $sth = $dbh->prepare_cached(<<SQL);
select host
from log
where stamp > from_unixtime(?)
SQL
$sth->execute($time);
[download]

where "stamp" is a datetime field.

Of course, if what the original poster really wants is a report of records from the last 7 days, all he/she'd have to use is something like this, which lets MySQL do all the work:

my $sth = $dbh->prepare_cached(<<SQL);
select host
from log
where to_days(now()) - to_days(stamp) > ?
SQL
$sth->execute(7);
[download]

where stamp is, again, a datetime field.

And finally, one more way of doing this--this will give you slightly different results than the last query, because the last query is giving you basically anything from the last 7 days; the following will give you anything *within* the last 7 days (a subtle difference):

my $sth = $dbh->prepare_cached(<<SQL);
select host
from log
where stamp > date_sub(now(), interval ? day)
SQL
$sth->execute(7);
[download]