Written by Admin on 2025-05-06

Sorting WordPress Posts by Custom Field (With Nulls)

WordPress, being one of the world's most popular CMS platforms, offers various ways to sort and display content on your website. However, sorting posts by custom fields can be a bit tricky, especially when dealing with null values.

In this article, we will explore how to sort WordPress posts by a custom field while also dealing with null values.

The Problem

Suppose you have created a custom field in WordPress called "price," which indicates the cost of a product. You want to sort all your products by price in ascending order. But when you try to do this, posts that don't have the custom field "price" set are not included in the results.

The reason for this is that WordPress, by default, ignores posts that have a null value in the custom field column.

The Solution

To include posts with null values in your sorting results, you need to use a custom function in your WordPress theme's functions.php file.

Firstly, you need to check if your custom field has a null value. If it does, assign a unique sorting value, such as "9999," to those posts. We can then use this unique sorting value to sort posts by price, including those with null values.

Here is the code for the custom function:

``` php function sortbyprice( $query ) {

if ( $query->is_main_query() && ! is_admin() ) {

    $query->set( 'meta_key', 'price' );
    $query->set( 'orderby', 'meta_value_num' );
    $query->set( 'order', 'ASC' );

    $query->set( 'meta_query', array(
        'relation' => 'OR',
        array(
            'key' => 'price',
            'compare' => 'EXISTS'
        ),
        array(
            'key' => 'price',
            'compare' => 'NOT EXISTS',
            'value' => '9999'
        )
    ));
}

}

addaction( 'pregetposts', 'sortby_price' ); ```

What this code does is sort the posts by the "price" custom field in ascending order. It also includes posts that either have the custom field key "price" or no "price" field set but a value of "9999," ensuring that posts with null values are also included in the sorting results.

Conclusion

By using this custom function, you can easily sort WordPress posts by custom fields and ensure that null values are also taken into account. This can be particularly useful when dealing with e-commerce websites and other product listing pages.

Remember to add this code to your theme's functions.php file and modify it accordingly for your specific custom field values. With this solution, you can efficiently sort and display your WordPress content while handling null values with ease.