Get all products from multiple categories (Woocommerce/Wordpress)

Question

I want to display all products from multiple categories at once.

When i want to display all products from one category my $args array looks like this:

$args = array(
   'post_type' => 'product',
   'product_cat' => 'backpacks',
   'orderby' => '_sku'
);

I remember that I can simply make an array inside my $args:

$args = array(
   'post_type' => 'product',
   'product_cat' => array(
      'backpacks','accessoires',
),
   'orderby' => '_sku'
);

But it gives me the following error:

Warning: urlencode() expects parameter 1 to be string, array given in C:\xampp\htdocs\live\wp-includes\formatting.php on line 4312

I know this is a simple thing but i cant figure out why its not working. Thanks for any help!

Answer 1

Please try below snippet.

$sortcolumn = 'ID';
$prod_categories = array(12, 17); //category IDs
$product_args = array(
    'numberposts' => -1,
    'post_status' => array('publish', 'pending', 'private', 'draft'),
    'post_type' => array('product', 'product_variation'), //skip types
    'orderby' => $sortcolumn,
    'order' => 'ASC',
);

if (!empty($prod_categories)) {
    $product_args['tax_query'] = array(
        array(
            'taxonomy' => 'product_cat',
            'field' => 'id',
            'terms' => $prod_categories,
            'operator' => 'IN',
    ));
}

$products = get_posts($product_args);