Query Posts in a Predefined Order

Question

I am using the query_posts function to list a 10 specific posts which lookup by post id.

I have an array which looks like this..

Array
(
    [0] => 17983
    [1] => 17932
    [2] => 18030
    [3] => 18016
    [4] => 17972
    [5] => 18013
    [6] => 18035
    [7] => 17959
    [8] => 18020
    [9] => 18039
)

I would like to query posts showing it in that specific order, however with my code it shows them in a random order of its own.

Here is the argument I use for query posts:

$args = array(
    'post_type' => 'post',
    'post__in' => $post_ids,
    'numberposts'     => 10,
);

$post_ids is the array which I have posted above.

How can I alter my code to query the posts and show them in the order of the array?

Answer 1

If the query is only for a small number of posts, then as linked to by Alex you can sort in php. However, this does not scale well.

As suggested by Kovshenin - a better alternative is to use posts_orderby filter:

$post_ids = array(83,24,106,2283,14);
$args = array(
    'post_type' => 'post',
    'post__in' => $post_ids,
    'numberposts'     => 10,
);

//Callback to filter the ORDER BY part of the query
function wpse67823_orderby_post_in($orderby, $query){
     global $wpdb;

     //Remove it so it doesn't effect future queries
     remove_filter(current_filter(), __FUNCTION__);

     $post__in = implode(',',$query->get('post__in'));

     return "FIELD( {$wpdb->posts}.ID, $post__in )";
 }

//Add filter and perform query
add_filter('posts_orderby','wpse67823_orderby_post_in',10,2);
$wpse67823_query = new WP_Query($args);

3.5+

WordPress 3.5 will see an additional value accepted by WP_Query for orderby: 'post__in'. See this trac ticket: http://core.trac.wordpress.org/ticket/13729

Answer 2

Based on @Stephen Harris answer, for Wordpress 3.5+ the easiest option seems to be ordering by post__in.

Here is the example:

$post_ids = Array(12, 15, 18, 8, 10, 5);

$args = array(
  'post_type' => 'post',
  'post__in' => $post_ids,
  'numberposts' => 10,
  'orderby' => 'post__in'
);
$posts = WP_Query($args); // or any other method that uses WP_Query args e.g. get_posts()

// as a result you will get posts in order: 12, 15, 18, 8, 10, 5

I've tested that myself on a Wordpress 4.7 site and it works as expected.

Answer 3

You will need to hijack the resulting SQL query during posts_orderby and use MySQL's ORDER BY FIELD() function with a comma-separated list from your array. Here's more info about the FIELD function: http://www.electrictoolbox.com/mysql-order-specific-field-values/

I did this quite some time ago when I had Sphinx return a list of post IDs ordered by relevance, so I had to select them with WP_Query in that very same order. FIELD() during the posts_orderby filter worked like a charm.

Also, if you're using query_posts to alter the main query, it's not the best way to do it. @Alex mentioned WP_Query, which is not really different from query_posts and is also a bad way to (make it seem like you) alter the main query.

The correct way would be to use the pre_get_posts action, and change the passed in by reference $query object. You can learn more about pre_get_posts here: http://codex.wordpress.org/Plugin_API/Action_Reference/pre_get_posts

Hope that's helpful. Cheers!

Answer 4

Here is a simpler Workaround to achieve this, simply create a custom field for each one of these posts with the same name ans set your desired order, ex:

• for post with id = 17983 set a custom field named my_custom_order = 1
• for post with id = 18030 set a custom field named my_custom_order = 2
• for post with id = 18016 set a custom field named my_custom_order = 3
• you get the point

then in your query simply order by that custom field:

$args = array(
    'post_type' => 'post',
    'post__in' => $post_ids,
    'posts_per_page' => 10,
    'meta_key' => 'my_custom_order',
    'orderby' => 'meta_value',
    'order' => 'ASC'
);

Note: Once you do that (set the custom field for these posts) you can remove the 'post__in' => $post_ids, parameter since only posts with the custom field of my_custom_order will be queried from the database.

Answer 5

First of all, don't use query_posts(), use WP_Query().

Second, change your array to just the post ids.

from:

[0] => 17983
[1] => 17932

to

array( 17983, 17932 )

EDIT: Look HERE for a reference.