How to Get Post ID of Parent Loop in Nested Loop - php

Question

I'm trying to figure out how to get the current post ID from my main wp_query loop to work in the nested loop..
I've added my loops below with most HTML removed to make it cleaner to see.
I need to replace the "16" where it says "$currentID = 16;" in the nested loop with the actual current post ID from the main loop.
<?php $related_query = new WP_Query( 'post_type=post&posts_per_page=-1' ); ?>
<?php if( $related_query->have_posts() ): ?>
<?php while ( $related_query->have_posts() ) : $related_query->the_post(); ?>
<?php the_ID(); ?>
<?php the_time('F j, Y'); ?>
<?php the_category(); ?>
<?php echo get_edit_post_link(); ?>
<?php echo get_post_meta(get_the_ID(), 'cf_meta-desc', true); ?>
<?php echo get_post_meta(get_the_ID(), 'cf_xray', true); ?>
<?php the_tags(); ?>
<ul>
<h4>Recommended Articles</h4>
<?php
$related_cfs = get_post_meta( get_the_ID(), 'cf_related' );
foreach($related_cfs as $related_cf) {
echo '<li>';
echo '<span class="related-links__id">' .$related_cf. '</span>';
echo '<span class="related-links__title"><a target="_blank" href="' .get_permalink($related_cf). '">' .get_the_title($related_cf). '</a></span>';
echo '<span class="related-links__edit"><a target="_blank" href="' .get_edit_post_link($related_cf). '">edit</a></span>';
echo '</li>';
} ?>
</ul>
<?php global $post;$backup=$post; //saves main query data before calling nested query ?>
<!-- BEGIN NESTED LOOP -->
<?php $referral_query = new WP_Query( 'meta_key=cf_related&posts_per_page=-1' ); ?>
<ol>
<h4 class="referring-links__header">Linkbacks (<?php
$meta_key = 'cf_related';
$currentID = 16;
$sql = "SELECT count(DISTINCT pm.post_id)
FROM $wpdb->postmeta pm
JOIN $wpdb->posts p ON (p.ID = pm.post_id)
WHERE pm.meta_key = '$meta_key'
AND pm.meta_value = '$currentID'
";
$count = $wpdb->get_var($sql);
echo "$count";
?>)
</h4>
<?php while ( $referral_query->have_posts() ) : $referral_query->the_post(); ?>
<?php
$currentID = 16;
$arrayCFrelated = get_post_custom_values('cf_related');
if (in_array($currentID, $arrayCFrelated))
{ ?>
<li>
<?php the_ID(); ?>
<?php the_title(); ?>
<?php echo get_edit_post_link(); ?>
</li>
<?php } ?>
<?php endwhile; ?>
</ol>
<!-- END NESTED LOOP -->
<?php $post=$backup; //brings back main query data before called nested query ?>
<?php echo get_post_meta(get_the_ID(), 'cf_img-feature', true); ?>
<?php endwhile; ?>
<?php else: ?>
<p class="center">Nothing found.</p>
<?php endif; ?>
<?php wp_reset_query(); ?>

Answer 1

The code you posted is very hard to read because it is all nested and distributed between opening and closing php tags.
First of all - You should consider to get familiar with functions and objects as an alternative to nest everything within the same loop. This will also help other developers who work with you to understand your code.
As for your problem. Try using other types of loops to get indices within the loop. For example:
for ($i1=0; $i1 < count($yourarray); $i1++) {
// ...
echo "index: $i1 <br />";
echo "value: {$yourarray[$i1]}";
}
or
foreach ($array AS $idx => $value) {
// ...
echo "index: $idx <br />";
echo "value: $value";
}

Answer 2

I know this question is old but I run into the same issue recently.
If you have a main loop and want to get the ID (or any other data) of the current post to be used inside of a nested wp_query then use the global $post object.
Using 'get_the_id()' inside of the nested wp_query will return the id of the current post in the nested wp_query and not the main query
Example:
$post_id = $post->ID;