count post meta values

Question

I have a custom function to count downloaded times for a specific file attached in the post, but i want to display the count of whole post in my website

post meta = download_times

and how to skip time out error message ?

Answer 1

Thank You @prosti for your answer I made Thise small code based on your answer and it works for me

global $post;
$query_args = array(
            'post_type' => 'post',
            'post_status' => 'publish',
            'order' => 'DESC',
            'posts_per_page' => -1,
            'cat' => 1,
            // 'fields' => 'SUM(amount_to_paid)',
        );

$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 + intval(get_post_meta(get_the_id(),'download_counter' ));
    }
}
echo $sum ;