WP_Query使用派生变量作为排序依据

Question

I am trying to order my posts by a value that is derived from getting the user's lat/long location information, and the same information for the post.

I already have the functions in place to get the user and post distance, so do not need that, but need to know how to code my args for wp_query.

My initial wp_query is

 array(
  "post_type" => "babysitters",
  "post_status" => "publish",
  "orderby" => "date",
  "order" => "DESC",
  "posts_per_page" => -1
);

I have a function that returns the distance value between the current user and the post, and would like to use this value to change the default sort order.

Here is my code for finding the distance (which works without issues)

function distance($lat1, $lon1, $lat2, $lon2, $unit) {

  $theta = $lon1 - $lon2;
  $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
  $dist = acos($dist);
  $dist = rad2deg($dist);
  $miles = $dist * 60 * 1.1515;
  $unit = strtoupper($unit);

  if ($unit == "K") {
    return ($miles * 1.609344);
  } else if ($unit == "N") {
      return ($miles * 0.8684);
    } else {
        return $miles;
      }
}

function user_distance_compare() {

$user_id = bp_loggedin_user_id();
$user_location = get_user_meta($user_id, 'geocode_321', false); 
$user_loc = implode(',', $user_location);
$commapos = strpos($user_loc, ",");
$loc_len = strlen($user_loc);
$user_lat = substr($user_loc,0,$commapos);
$user_lng = substr($user_loc,($commapos + 1), ($loc_len - $commapos));
$post_id = get_the_ID();
$post_location = get_field('suburb', $post->ID);
$post_lat = $post_location['lat'];
$post_lng = $post_location['lng'];
//var_dump($user_lat);
//var_dump($user_lng);
//var_dump($post_lat);
//var_dump($post_lng);
$distance = distance($user_lat, $user_lng, $post_lat, $post_lng, "K");
return $distance;
}

How do I assign the returned distance so it matches with a post ID, that I can then use this derived distance to do my sort?

IE Post Distance

• 1 - 33.4
• 2 - 14.2
• 3 - 1.7
• 4 - 12.5

In the end I'd like to have it displayed in distance order, so that it would be 3,4,2,1 as the post order.

By SQL it would read Select DISTINCT post_id, distance (where it has been derived from the post information) from posts where post_type = 'babysitters' order by distance

Anyone able to help?

Answer 1

If you're getting the distance using a function, I'd built an array of post IDs sorted by distance. Then use the 'post__in' parameter of WP_Query to get only those items that you want. You can also use 'post__in' for the orderby parameter.

$babysitters = array(
  '10' => 23,
  '12' => 345,
  '18' => '27
)

get_posts(array(
  'post_type' => 'babysitter',
  'posts_per_page' => -1,
  'post__in' => $babysitters,
  'orderby' => 'post__in'
));