我想在查询具有平均评论评级的类别页面（比如一次5000个产品）时节省一些PHP内存，所以我想在每次手动批准新评论时保存评论的平均评级。

我想实现的是，每当我在administration中点击“APPROVE”按钮时，它都会运行这些php脚本。

function average_rating() {
global $wpdb;

$post_id = get_the_ID();

$ratings = $wpdb->get_results("

    SELECT $wpdb->commentmeta.meta_value

    FROM $wpdb->commentmeta

    INNER JOIN $wpdb->comments on $wpdb->comments.comment_id=$wpdb->commentmeta.comment_id

    WHERE $wpdb->commentmeta.meta_key=\'rating\' 

    AND $wpdb->comments.comment_post_id=$post_id 

    AND $wpdb->comments.comment_approved = 1

    and trim(coalesce($wpdb->commentmeta.meta_value, \'\')) <>\'\'

    ");

$counter = 0;

$average_rating = 0;    

if ($ratings) {

    foreach ($ratings as $rating) {

        $average_rating = $average_rating + $rating->meta_value;

        $counter++;

    } 

    //round the average to the nearast 1/2 point

    return (round(($average_rating/$counter)*2,0)/2);  

} else {

    //no ratings

    return \'0\';

}

}

 $ar = average_rating();
 add_post_meta( $post->ID, \'summary\', $ar );