Get Wordpress posts so things like get_post_thumbnail_id don't make a database call

Question

Is there a way to fetch Wordpress posts so that meta calls don't actually do database calls?

For example, I currently have:

$args = array(
  'posts_per_page' => 1000,
  'post_type' => 'portfoliosample'
  );
$query = new WP_Query($args);
while($query->have_posts()):
  $query->the_post();
  $style = '';
  if(has_post_thumbnail($post->ID)){
    $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' );
    $largeurl = $image[0];
    $style = ' style="background-image:url('.$largeurl.');"';
  }

?>
    <li id="post-<?php the_ID(); ?>" <?php post_class('half'); ?>>
      <a href="<?php the_permalink()?>"<?php echo $style?> ng-click="lightbox('portfolio','<?php the_permalink()?>')">
        <h3 class="entry-title caps"><?php echo strtoupper(the_title('', '', false)); ?></h3>
        </a>
    </li>
<?php
endwhile;

Things like the_title() do not make database calls because post has that information. However, $post seemingly does not have the post's thumbnail ID or that thumbnail's image source.
If I do a custom query like this:

global $wpdb;
$query = "
    SELECT posts.*
    FROM $wpdb->posts posts
    WHERE posts.post_type = 'portfoliosample'
    AND posts.post_status = 'publish'
    ORDER BY posts.menu_order ASC
";
$pageposts = $wpdb->get_results($query, OBJECT);
if($pageposts)
{
    global $post;
    foreach($pageposts as $post)
    {
        setup_postdata($post);
        $style = '';
        if(has_post_thumbnail($post->ID)){
            $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' );
            $largeurl = $image[0];
            $style = ' style="background-image:url('.$largeurl.');"';
        }
        ?>
        <li id="post-<?php the_ID(); ?>" <?php post_class('half'); ?>>
            <a href="<?php the_permalink()?>"<?php echo $style?> ng-click="lightbox('portfolio','<?php the_permalink()?>')">
                <h3 class="entry-title caps"><?php echo strtoupper(the_title('', '', false)); ?></h3>
            </a>
        </li><!-- #post-## -->
        <?php
    }
}

Can I fetch the meta at the same time but still allow functions like get_post_thumbnail() ? I was hoping that setup_postdata() would have a way to handle that.

Answer 1

There isn't a way to do what I want. You either have to do everything those functions do manually, or allow them to make database calls.

Answer 2

Try this (untested and probably a bit broken, but should get you moving in the right direction):

$querystr = "
SELECT $wpdb->posts.*, $wpdb->postmeta.*
FROM $wpdb->posts
LEFT JOIN $wpdb->postmeta ON {$wpdb->postmeta}.id = {$wpdb->post}.id
WHERE $wpdb->posts.post_status = 'publish' 
AND $wpdb->postmeta.key = '_thumbnail_id'
AND $wpdb->posts.post_type = 'portfoliosample'
";

$pageposts = $wpdb->get_results($querystr, OBJECT);

and then loop through it like this:

<?php if ($pageposts): ?>
<?php global $post; ?>
<?php foreach ($pageposts as $post): ?>
<?php setup_postdata($post); ?>

<div class="post" id="post-<?php the_ID(); ?>">
<h2><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>">
    <?php the_title(); ?></a></h2>
    <small><?php the_time('F jS, Y') ?> <!-- by <?php the_author() ?> --></small>
    <div class="entry">
      <?php the_content('Read the rest of this entry »'); ?>
    </div>
    <p class="postmetadata">Posted in <?php the_category(', ') ?> | <?php edit_post_link('Edit', '', ' | '); ?>  
    <?php comments_popup_link('No Comments »', '1 Comment »', '% Comments »'); ?></p>
</div>
<?php endforeach; ?>
<?php else : ?>
    <h2 class="center">Not Found</h2>
    <p class="center">Sorry, but you are looking for something that isn't here.</p>
    <?php include (TEMPLATEPATH . "/searchform.php"); ?>
<?php endif; ?>

You'll have to get the actual meta values from $post instead of using the WP post meta functions, but at least you'll have the data in one query.

If you want to take it further and grab the full file information, you'll have to do additional joins (again, I'm sure it's not written correctly, but it'll give you the right idea, and instead of * you'll want to grab only the fields you need)

$querystr = "
SELECT post.*, pm.*, attach.*
FROM $wpdb->posts post
LEFT JOIN $wpdb->postmeta pm ON pm.id = {$wpdb->post}.id
LEFT JOIN $wpdb->posts attach ON attach.id = pm.id
WHERE post.post_status = 'publish' 
AND pm.key = '_thumbnail_id'
AND post.post_type = 'portfoliosample'
";

$pageposts = $wpdb->get_results($querystr, OBJECT);