$args = array(
'posts_per_page' => -1,
'post_type' => 'product_variation',
'meta_query' => array(
array(
'key' => '_sku',
'value' => $_GET['refe'],
'compare' => '='
)
)
);
$posts = get_posts($args);
$get_post_ids = array();
foreach ($posts as $post) {
echo $get_post_ids[] = $post->ID;
}
print_r($get_post_ids);