Question

I’m having a small query issue that maybe you can help me with. I am trying to get all comments from a post that has a particular comment meta. This is what I have so far:

$comments = $wpdb->get_results("SELECT * FROM $wpdb->comments INNER JOIN wp_commentmeta WHERE comment_post_ID = '256' AND comment_approved = '1' AND meta_key = 'bestcomment' AND meta_value = 'yes' ");  ?>
<ul id="bestcomment">
<h2>Best Comment</h2>
<?php
if ( $comments ) : foreach ( (array) $comments as $comment) :
echo  '<li class="recentcomments">' . sprintf(__('%1$s on %2$s'), get_comment_author_link(), '<a href="'. get_comment_link($comment->comment_ID) . '">' . get_the_title($comment->comment_post_ID) . '</a>') . '</li>';
endforeach; endif;?></ul>

This post should only have one comment. Unfortunately, the query is displaying the same result 24 times. So there has to be something wrong with the loop. Thoughts?

Answer 1

There is nothing wrong with the loop. The problem is that your query produces cartesian product (CROSS JOIN) because you didn’t specify the column on which the two tables should be link.

The fastest answer I can give is to define the linking columns on the ON clause,

$comments = $wpdb->get_results("
SELECT * 
FROM $wpdb->comments a
      INNER JOIN wp_commentmeta b
         ON a.ColumnName = b.Columnname           <== define here
WHERE comment_post_ID = '256' AND 
      comment_approved = '1' AND 
      meta_key = 'bestcomment' AND 
       meta_value = 'yes' ");

just change ColumnName into the real name of the column in your table.

To learn more about JOIN, please take a look at the article below,

• Visual Representation of SQL Joins