Your first three solutions are wrong. You assume that every day has 86400 seconds. 
use POSIX       qw( strftime );
use Time::Local qw( timelocal );

# Pretend we're executing at 12:00:05 am on Mar 12th, 2008.
# The DST time zone change occured on Mar 9th, 2008 here.
my $time = timelocal(5,0,0,12,3-1,2008);

my $offset = 7;
my $date = strftime "%Y-%m-%d",
    localtime($time - $offset * 86400);

print("Expecting: 2008-03-05\n");
print("Received:  $date\n");

[download]
Expecting: 2008-03-05
Received:  2008-03-04

[download]

See Re: Get the date (MySQL style) for X days ago for a solution.

In reply to Re^2: Get the date (MySQL style) for X days ago by ikegami
in thread Get the date (MySQL style) for X days ago by mbreyno

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