WP_Query orderby not working on custom post_type

Question

I try to order a WP_Query of a custom post type 'entry' by a meta value 'votes', but it keeps showing up ordered by date. My code:

$args = array(
        'post_type' => 'entry',
        'orderby' => 'votes',
        'order' => 'DESC',
        'posts_per_page' => 10,
        'post_status' => 'publish'
    );
$loop = new WP_Query($args);

When I evaluate $loop->request in xDebug, I get this, which indicates the results are indeed ordered by post_date DESC:

SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  WHERE 1=1  AND wp_posts.post_type = 'entry' AND ((wp_posts.post_status = 'publish'))  ORDER BY wp_posts.post_date DESC LIMIT 0, 10

Do I need to use meta_query to order on custom post type meta fields? I thought that was only needed when you want to compare/restrict results based on custom meta?

Answer 1

OK, I figured it pour reading about Orderby Parameters in WP_Query more carefully. I needed to set votes to meta_key and orderby to meta_value_num:

$args = array(
        'post_type' => 'entry',
        'meta_key' => 'votes',
        'orderby' => 'meta_value_num',
        'order' => 'DESC',
        'posts_per_page' => 10,
        'post_status' => 'publish'
    );
$loop = new WP_Query($args);

Answer 2

<?php
$args = array(
  'post_type' => 'entry',
  'meta_key'       => 'start_date', //Meta field value name 
  'meta_type'      => 'DATETIME',
  'order'          => 'DESC',
  'orderby'        => 'meta_value_num',
  'posts_per_page' => 10,
  );
  $query = new WP_Query( $args );

  if( $query->have_posts() ) : while( $query->have_posts() ) : $query->the_post();
  //Your Front End filed Value
  //Such as
  ?>
  <h4>  <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a> </h4>
  <?php if( get_field('start_date')) { ?><strong> Start Date: </strong><?php echo the_field('start_date'); ?><?php } ?> <br>
  <?php the_excerpt(); ?> <a href="<?php the_permalink(); ?>">Read More &raquo;</a>

  <?php endwhile; endif; wp_reset_postdata(); ?>