How to get sum of meta_values of a meta_key in wp_query according to conditions

Question

Here is my query args :

 $query_args = array(
            'post_type' => 'rented_properties',
            'post_status' => 'publish',
            'order' => 'DESC',
            // 'fields' => 'SUM(amount_to_paid)',
        );


        $my_querys = null;
        $my_querys = new WP_Query($query_args);

My meta key is amount_to_paid, and I want to get the sum all the meta_values of this query condition. Please suggest your answer with query_args.

My Scenario : I have 1000 posts and each with meta_key amount_to_paid and it has some value. Now I filter 20 posts and want to get sum of meta_value of amount_to_paid . Did you got me now?

Answer 1

WP_Query gets posts from the database, but it's not a generic SQL query class, it should really be called WP_Post_Query, as WP_Query implies it can do any SQL.

As a result, you need to do several things:

1. Grab the posts you need
2. Get their meta values for amount_to_paid using get_post_meta
3. Add those values up using the basic PHP maths + - / * = += -=

So:

$sum = 0;
$query = new WP_Query($query_args);
if ( $query->have_posts() ) {
    while( $query->have_posts() ) {
        $query->the_post();
        // do the processing for each post
        $sum = $sum + get_post_meta( ... );
    }
}
echo esc_html( $sum );

Answer 2

You can try this code.

global $wpdb;
$meta_key = 'link_click_counter';
$all_downloads = $wpdb->get_var($wpdb->prepare("
                                  SELECT sum(meta_value) 
                                  FROM $wpdb->postmeta 
                                  WHERE meta_key = %s", $meta_key));

echo $all_downloads;