Sum custom_meta value of all posts

It will need some custom PHP work to do this, but it’s not to hard.

$result = $wpdb->get_results ("SELECT meta_value FROM ".$wpdb->post_meta." WHERE meta_key = 'project-cost'");
$total = 0;
foreach ($result as $row) {
   $total += $row->meta_value;
}
echo $total;

Of course… That is assuming that the values for project_cost are stores as plain numbers and not text. if they are text, you can always use something extra like doubleval() to get a numeric value for it.

Hey Michael,
Thanks for your reply.

I just tried the code, and all I get is ‘0’.

Maybe this will help… this is the code that I use to display the cost for each project:

<?php
	echo '<ul>';

	query_posts('category_name=active-project');
	while (have_posts()) : the_post();

	$cost = get_post_meta($post->ID, 'project_cost', true);
	echo '<li>'.$cost.'</li>';

	endwhile;

	echo '</ul>';
?>

The above code will output something like this:
100.00
150.00
120.00
200.00

What I need to do, is get the sum of all the above amounts.

In the code that I had in my original post there had ‘project-cost’ instead of ‘project_cost’. That might make a difference.

What do you get as a result from each row in my code when you make that change?