Wordpress sql query for last comment date - php

Question

i would like to get date gmt of latest comment for post ID. Result i would like to get as a string.
Can somebody help me how to set result into string:
function GetLastCommentDate( $postId ) {
global $wpdb;
$dateOutput = '0000-00-00 00:00:00';
$commentRes= $wpdb->get_results("SELECT DISTINCT `comment_date_gmt` FROM `wp_comments` WHERE `comment_approved` ='1' AND `comment_post_ID` = '". $postId. "' ORDER BY `comment_date_gmt` DESC LIMIT 1");
if(!empty($commentRes)) {
$dateOutput = ...........
}
return $dateOutput;
}
One answer is like this:
$commentRes= $wpdb->get_results("SELECT DISTINCT `comment_date_gmt` as `comment_date_gmt` FROM `wp_comments` WHERE `comment_approved` ='1' AND `comment_post_ID` = '". $postId. "' ORDER BY `comment_date_gmt` DESC LIMIT 1");
if(!empty($commentRes)) {
foreach($commentRes as $comment) {
$dateOutput=$comment->comment_date_gmt;
}
}
return $dateOutput;
But how to avoid foreach loop? There is only one row (sql limit set to 1).

Answer 1

You need not query wordpress database directly. WP provides an API to retrieve this.
$comments = get_comments( array(
'post_id' => $post->ID,
'orderby' => 'comment_date_gmt',
'status' => 'approve',
'number' => 1
) );
Check out this API reference. Specifying number as 1 returns only the last comment.
The date value for last comment can be retrieved as $comments[0]['date']
Now that you want to use this from outside, include the following at top of your php code
require('/the/path/to/your/wp-blog-header.php');
Check out this wordpress doumentation
If you get an out of loop error try adding this code.
The loop starts here:
<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
and ends here:
<?php endwhile; else: ?>
<p><?php _e('Sorry, no posts matched your criteria.'); ?></p>
<?php endif; ?>

Answer 2

I think you want something like this;
$commentRes= $wpdb->get_row(
"SELECT `comment_date_gmt` FROM `wp_comments` ".
"WHERE `comment_approved` ='1' AND `comment_post_ID` = '$postId' ".
"ORDER BY `comment_date_gmt` DESC LIMIT 1");
if(!empty($commentRes))
$dateOutput = date("Y-m-d H:i:s", $commentRes->comment_date_gmt);

Answer 3

I've stumbled upon this while searching for something else. I know that the question is old, and the aswers too, but somebody can find it like I did, and I'd like to add another updated solution.
function GetLastCommentDate( $postId ) {
$dateOutput = false; //this will make easier to check if there are no comments
//get_comments() args https://codex.wordpress.org/Function_Reference/get_comments
$args = array(
'post_id' => $postId, //just comments of this post
'number' => 1, //just one comment
'order_by' => 'comment_date_gmt', //order by comment date gmt
'order' => 'DESC', //latest first
);
//retrieve comments
$comments = get_comments($args);
if ($comments){
$dateOutput = $comments[0]->comment_date;
}
return $dateOutput;
}
And you can use it wherever you want like this:
$postId = '12345';
$lastCommentDate = GetLastCommentDate($postId) ?: 'Never';
echo $lastCommentDate;