my $day_now;
my $day_old = "first";
my $dif = 1;
my @dif_array = ();

while (my @arr2 = $sth_prepare->fetchrow_array()) {
   $day_now = substr($arr2[0],8,2);
   $dif = $day_now - $day_old unless $day_old eq 'first';
   push @dif_array, $dif;
   for (@dif_array) {
      push @array, 0 while (0..$_);
   }
   push @array, $arr2[1];
   $day_old = $day_now;
}