Set the highest priced variation as default in Woocommerce variable products

I have a lots of products with variations in my woocommerce installation. None of them is preselected as default when user browses to any product page.

Manually, selecting them would be a tedious job. Additionally, new products and variations are imported automatically on daily basis using SQL script.

I would like to have preselected product variation with highest price for any user that browses to any product page which has variable product.

How to do that?

Here it is an automated solution, that will do the job each time a variable product is called/browse by a customer.

The variable product will be updated with a default variation that has the highest price.

This will be done once only as I set a custom post meta key/value each time a variable product has been updated.

The code:

add_action( 'template_redirect', 'set_default_variation_job' );
function set_default_variation_job() {
    if ( ! is_product() || is_admin() ) return;

    global $wpdb, $post;

    // Get an instance of the WC_Product object
    $product = wc_get_product($post->ID);
    $product_id = $post->ID;

    // Check if default variation has been updated, if yes we exit
    if( get_post_meta( $product_id, '_default_variation_updated', true ) ) return;

    // Only for variable products
    if ( $product->is_type( 'variable' ) ) {

        $max_price = $product->get_variation_price('max', true); // Get Max variation price

        // SQL Query: Get the variation ID of the  max variation price
        $result = $wpdb->get_col("
            SELECT pm.post_id FROM {$wpdb->prefix}postmeta as pm
            INNER JOIN {$wpdb->prefix}posts as p ON pm.post_id = p.ID
            WHERE p.post_type LIKE 'product_variation' AND p.post_parent = $product_id
            AND pm.meta_key LIKE '_price' and pm.meta_value = $max_price
        ");
        $variation_id= reset($result); // get the first variation ID as a string

        // Get an instance of the WC_Product_Variation object
        $variation = wc_get_product($variation_id);
        $default_attributes = array();

        // Loop through this variation attributes and format them
        foreach( $variation->get_variation_attributes() as $key => $value ){
            $taxonomy = str_replace( 'attribute_', '', $key );
            $default_attributes[ $taxonomy ] = $value;
        }

        // Set the default variation attributes in the Variable product
        $product->set_default_attributes( $default_attributes );
        // Set a meta data flag to avoid update repetitions
        update_post_meta( $product_id, '_default_variation_updated', '1' );
        $product->save(); // Save the data
    }
}

Code goes in function.php file of your active child theme (active theme).

Tested and works.

Go to the file woocommerce/templates/single-product/add-to-cart/variable.php and add the following line: