while ($book_id = $sth->fetchrow_array()) {
    $booklist_1{$book_id} = 1;
}

##</code><code>##

$sql = "select update_id, title from booklist_table where (book_id = ?) order by update_id desc limit 1";
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr);

foreach $book_id (keys %booklist_1) {

    $sth->execute($book_id) or die("Could not execute!" . $dbh->errstr);
    ($update_id, $title) = $sth->fetchrow_array();
    $booklist_1{$book_id}{'update_id'} = $update_id;
    $booklist_1{$book_id}{'title'} = $title;

    print "$book_id > $booklist_1{$book_id}{'update_id'}\n";
}
$sth->finish;

##</code><code>##

$sql = "SELECT book_id FROM booklist_table WHERE (expected_publcn_date >= '".$start_date."' AND expected_publcn_date <= '".$end_date."')";
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr);
$sth->execute() or die("Could not execute!" . $dbh->errstr);
while ($book_id = $sth->fetchrow_array()) {
    $booklist_1_temp{$book_id} = 1;
}
$sth->finish;

$sql = "select update_id, title from booklist_table where (book_id = ?) order by update_id desc limit 1";
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr);

foreach $book_id (keys %booklist_1_temp) {

    $sth->execute($book_id) or die("Could not execute!" . $dbh->errstr);
    ($update_id, $title) = $sth->fetchrow_array();
    $booklist_1{$book_id}{'update_id'} = $update_id;
    $booklist_1{$book_id}{'title'} = $title;

    print "$book_id > $booklist_1{$book_id}{'update_id'}\n";
}
$sth->finish;