假设您的产品是定制贴子，您可以这样做：

add_action(\'wp_insert_post\', \'do_stuff\'); // when product is created
add_action(\'save_post\', \'do_stuff\' ); // on product update
   function do_stuff( $post_id ) {

       // Making sure this runs only for products
       $slug = \'product_post\';
       if ( $slug != $_POST[\'post_type\'] ) {
          return;
       }

       if (!get_post_meta( $post_id, \'new_price\', true )){
          $old_price = get_post_meta( $post_id, \'old_price\', true );
          update_post_meta($post_id, \'new_price\', $old_price);    
       }

}

// url: site.com/test-page?offset=0, change this by 50 (0,50,100,150,200,250...)

$offset = $_GET[\'offset\']; // start with 0
$args = [
         \'offset\'         => $offset,
         \'posts_per_page\' => 50, 
         \'post_type\'      => \'product_post\'
        ];

$the_query = new WP_Query( $args );
if($the_query->posts){

   foreach($the_query->posts as $product){

      if (!get_post_meta( $product->ID, \'new_price\', true )){
         $old_price = get_post_meta( $product->ID, \'old_price\', true );
         update_post_meta($product->ID, \'new_price\', $old_price);    
      }

   }

}else{
   echo \'Done!\';
}