Как найти свободный title?

$rel = $db->query("SELECT title 
    FROM ".PREFIX."_post 
	WHERE 1
    ORDER BY title ASC
    LIMIT 0, 500
	");

$blobInterval = range(1, 99999);

$bILength = 5;

$blobInterval = array_map(function($v) use ($bILength){
    return str_pad($v, $bILength, 0, STR_PAD_LEFT);
}, $blobInterval);

while ($row = $db->get_row($rel))
{
  if (!in_array($row['title'], $blobInterval))
  {
    echo "<a href="#" data-title="{$row['title']}">{$row['title']}</a>";
  }
}

$rel = $db->query("SELECT title 
    FROM ".PREFIX."_post 
    WHERE 1
    ORDER BY title ASC
    LIMIT 0, 500
    ");

$blobInterval = range(1, 99999);

$bILength = 5;

$blobInterval = array_map(function($v) use ($bILength){
    return str_pad($v, $bILength, 0, STR_PAD_LEFT);
}, $blobInterval);

$titlesArr = [];

while ($row = $db->get_row($rel))
{
  $titlesArr[] = $row['title'];
}

$arrayIntersect = array_intersect($blobInterval, $titlesArr);

$arrayDiff = array_diff($blobInterval, $arrayIntersect);

foreach($arrayDiff as $arrayDiffRow)
{

    echo '<a href="#" data-title="' . $arrayDiffRow. '">' . $arrayDiffRow . '</a>';

}