Set Content First Image As Featured Image Wordpress

$args = array(
	'post_type' => 'article',
	'numberposts' => -1,
	'post_status' => 'publish',
);
// Getting the posts
$articles = get_posts($args);

foreach ($articles as $key => $article) {
    // Find the first image
	$output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $article->post_content, $matches);
    
    // Remove the image size attribute from image url 
	$pattern = "~-\d+[Xx]\d+~";
	$replacement = "";
	$new_url = preg_replace($pattern, $replacement, $matches[1][0]);
    
    // Check if post don't has any featured image and the post content has any image
	if(! has_post_thumbnail($article->ID) && !empty($new_url)){
        // Getting the attachment id from image url
		$thumb_id = child_get_image_id($new_url);
        // Finally set the attachment a featured image of that post
		set_post_thumbnail($article->ID, (int)$thumb_id);
	}
}

// Getting the attachmentt id from image url
function child_get_image_id($image_url) {
	global $wpdb;
	$attachment = $wpdb->get_col($wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE guid='%s';", $image_url )); 

    return $attachment[0]; 
}