Show only “in stock” related products on WooCommerce single product page

Question

I would like to show only "in stock" related products on WooCommerce single product pages.

I know I can override single-product/related.php template file via My theme. Here below is the related code for this template:

<section class="related products">

    <h2><?php _e( 'You May Also Want', 'MyStore' ); ?></h2>

    <?php woocommerce_product_loop_start(); ?>

        <?php foreach ( $related_products as $related_product ) : ?>

            <?php
                $post_object = get_post( $related_product->get_id() );

                setup_postdata( $GLOBALS['post'] =& $post_object );

                wc_get_template_part( 'content', 'product' ); ?>
                
        <?php endforeach; ?>

    <?php woocommerce_product_loop_end(); ?>

</section>

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Is it possible making some changes to this file to only show "in stock" related products on WooCommerce single product page? Any help is appreciated.

Answer 1

Instead of editing template files, you can use woocommerce_product_related_posts_query dedicated filter hook to alter the query excluding "out of stock" products from displayed related products:

add_filter( 'woocommerce_product_related_posts_query', 'alter_product_related_posts_query', 10, 3 );
function alter_product_related_posts_query( $query, $product_id, $args ){
    global $wpdb;

    $query['join']  .= " INNER JOIN {$wpdb->postmeta} as pm ON p.ID = pm.post_id ";
    $query['where'] .= " AND pm.meta_key = '_stock_status' AND meta_value != 'outofstock' ";

    return $query;
}

Code goes in functions.php file of the active child theme (or active theme). Tested and works.

Related: Customize related products with a custom meta query in Woocommerce

Answer 2

UPDATE

Because when the 4 first products are out of stock it does not display anything (In case the default 4 products are shown) you could use the following snippet instead of overwriting the template file.

function filter_woocommerce_related_products( $related_posts, $product_id, $args ) {    
    foreach( $related_posts as $key => $related_post ) {        
        // Get product
        $related_product = wc_get_product( $related_post );
        
        // Is a WC product 
        if ( is_a( $related_product, 'WC_Product' ) ) {
            // Stock status
            $stock_status = $related_product->get_stock_status();
            
            // NOT instock
            if ( $stock_status != 'instock' ) {
                unset( $related_posts[$key] );
            }
        }
    }
    
    return $related_posts;
}
add_filter( 'woocommerce_related_products', 'filter_woocommerce_related_products', 10, 3 );

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Overwriting the template file

There are always multiple solutions but 1 of them could be by overwriting the template file.

https://github.com/woocommerce/woocommerce/blob/02cf0dfaed5923513de0c88add597d1560c2cfd2/templates/single-product/related.php

• This template can be overridden by copying it to yourtheme/woocommerce/single-product/related.php

---

Replace

<?php foreach ( $related_products as $related_product ) : ?>

        <?php
        $post_object = get_post( $related_product->get_id() );

        setup_postdata( $GLOBALS['post'] =& $post_object ); // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited, Squiz.PHP.DisallowMultipleAssignments.Found

        wc_get_template_part( 'content', 'product' );
        ?>

<?php endforeach; ?>

With

<?php foreach ( $related_products as $related_product ) : ?>

    <?php
    $stock_status = $related_product->get_stock_status();

    if ( $stock_status == 'instock' ) {
        
        $post_object = get_post( $related_product->get_id() );

        setup_postdata( $GLOBALS['post'] =& $post_object ); // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited, Squiz.PHP.DisallowMultipleAssignments.Found

        wc_get_template_part( 'content', 'product' );
    }
    ?>

<?php endforeach; ?>

Answer 3

This is what I've been using, and it works for me:

add_filter( 'woocommerce_related_products', 'mysite_filter_related_products', 10, 1 );
function mysite_filter_related_products( $related_product_ids )
{

if (!is_admin()) {
    foreach ($related_product_ids as $key => $value) {
        $relatedProduct = wc_get_product($value);
        if (!$relatedProduct->is_in_stock() ) {
            unset($related_product_ids["$key"]);
        }
    }

    return $related_product_ids;
  }
}