Check if post has gallery

Heres a Snippet I made, not sure if it’s the right thing to do, but it worked for me on a “from Scratch” theme I built:

//place within the PHP on your functions.php page

function mypost_has_gallery($postid)
	{
		//SELECT * FROM <code>wp_posts</code> WHERE
		//((<code>wp_posts</code>.<code>post_type</code>="attachment")
		//AND (<code>wp_posts</code>.<code>post_parent</code>="postID")
		//AND (LOCATE("image",<code>wp_posts</code>.<code>post_mime_type</code>)>0))
		global $wpdb;
		$table = $wpdb->prefix . "posts";
		$sql = "SELECT * FROM <code>&quot; . $table . &quot;</code> WHERE ((<code>&quot; . $table . &quot;</code>.<code>post_type</code>=\"attachment\") AND (<code>&quot; . $table . &quot;</code>.<code>post_parent</code>=\"" . $postid ."\") AND (LOCATE(\"image\",<code>&quot; . $table . &quot;</code>.<code>post_mime_type</code>)>0))";
		if ( $wpdb->get_var($sql) != 0 ){
			return true;}
		else{
			return false;
		}}

//Insert on the page
<?php $postid = get_the_ID();
if ( mypost_has_gallery($postid) ) {?>
        	//do something
       <?php } ?>

Here is what’s on my page (There’s a default image for pages in the last else statement)

<div id="postimage" >
		<?php if( has_post_thumbnail()) {
				//check for featured image on page or post
                $image_src = wp_get_attachment_image_src( get_post_thumbnail_id(), "full" );
                echo "<img border=\"0\" src=\"". $image_src[0] ."\" >"; //IE image Border 0 for images inside links
        		} // if the page doesn't have a featured image, but instead has a gallery of attached images do this...
				else if ( mypost_has_gallery($postid) ) {
            		// Place the Gallery automagically on the page
            		echo do_shortcode('[gallery link="post"]');
				} // if there is no image fallback to this default
				else { ?>
                	<img src="<?php bloginfo('template_directory'); ?>/featimg.png" alt="<?php the_title(); ?>" />
		<?php }	?>
       </div>

If that was clear as mud, I’ll try to de-obfuscate it, let me know.

I’m using this one since an year

<?php
if (strpos($post->post_content,'[gallery') !== false){
echo do_shortcode('[gallery]');
} else {
the_post_thumbnail();
}
?>