查找的正确键game_date_key 然后运行一次：

global $wpdb;
$posts = $wpdb->get_results("SELECT ID FROM ".$wpdb->prefix."posts" WHERE post_type=\'post\');
foreach ($posts as $post) {
    $old_date = get_post_meta($post->ID,\'game_date_key\',true);
    $new_date = date(\'d/m/Y\', strtotime($old_date));
    update_post_meta($post->ID,\'game_date_key\',$new_date,$old_date);
}