Order query by post meta value

Question

      //Displaying latest post per author on front page
  function filter_where($where = '') {
    global $wpdb;
    $where .= " AND vipwp_posts.id = (select id from {$wpdb->prefix}posts p2 where p2.post_status = 'publish' and p2.post_author = {$wpdb->prefix}posts.post_author order by p2.post_date desc limit 0,1)";
    return $where;
  }
  add_filter('posts_where', 'filter_where'); 

I would like to modify the code above: Is it possible change the order of the record from date by meta_value?

Example: CHANGE

order by p2.post_date

TO

meta_key='name_key' ORDER BY meta_value

---

Thanks, but if I remove post_where do not Displaying latest post per author

Answer 1

Take a look at the WordPress Codex: http://codex.wordpress.org/Plugin_API/Filter_Reference/posts_orderby

function edit_posts_orderby($orderby_statement) {
    $orderby_statement = "meta_value DESC";
    return $orderby_statement;
} add_filter('posts_orderby', 'edit_posts_orderby');

If you're making the WP_Query yourself you can change the orderby parameter to meta_value

Take a look here: http://codex.wordpress.org/Class_Reference/WP_Query

Answer 2

I think you can do this entirely from the pre_get_posts action. So try removing your posts_where filter and replacing it with:

function wpa_69199( $query ) {
        set_query_var( 'orderby', 'meta_value' );
        set_query_var( 'meta_key', 'name_key' ); //field you'd like to order by
}
add_action( 'pre_get_posts', 'wpa_69199' );

Note: there is no conditional logic here and all posts everywhere will be sorted this way.