$servername = "localhost";
$username = "xx";
$password = "xx";
$dbname = "xx";
$conn = new mysqli($servername, $username, $password, $dbname);
$sql = "SELECT * FROM aa_link";
$result = $conn->query($sql); ?> 

<?php header('Content-type: application/xml; ',true); ?> 

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"> 

<?php while($row = $result->fetch_assoc()) { ?> 

<url> 

<loc><![CDATA[<?php echo 'https://aa.com'.$row["aa_link"]; ?>]]></loc>

<changefreq>weekly</changefreq> 
<priority>0.7</priority> 

</url> 

<?php } ?> 

</urlset>