[建议]希望能显示购买了商品的用户邮箱 about tint-pro HOT 4 CLOSED

/**
 * 查找某个商品的购买用户的邮箱
 *
 * @param $product_id
 * @return array|null|object
 */
function tt_get_buyer_emails($product_id) {
    $cache_key = 'tt_product' . $product_id . '_buyer_emails';
    if($cache = get_transient($cache_key)) {
        return maybe_unserialize($cache);
    }

    global $wpdb;
    $prefix = $wpdb->prefix;
    $orders_table = $prefix . 'tt_orders';
    $sql = sprintf("SELECT `user_id` FROM $orders_table WHERE `deleted`=0 AND `order_status`=%d AND `product_id`=%d ORDER BY `id` DESC", OrderStatus::TRADE_SUCCESS, $product_id); 
    $results = $wpdb->get_col($sql);

    if(!$results || count($results) < 1) return null;

    $user_emails = $wpdb->get_col(sprintf("SELECT `user_email` FROM $wpdb->users WHERE ID IN (%s) AND wp_users.user_email<>''", implode(',', $results)));

    set_transient($cache_key, maybe_serialize($user_emails), 3600*24);
    return $user_emails;
}

function tin_get_buyer_emails($product_id) {
    $cache_key = 'tt_product' . $product_id . '_buyer_emails';
    if($cache = get_transient($cache_key)) {
        return maybe_unserialize($cache);
    }

    global $wpdb;
    $prefix = $wpdb->prefix;
    $orders_table = $prefix . 'tt_orders';
    $sql = sprintf("SELECT `user_id` FROM $orders_table WHERE `deleted`=0 AND `order_status`=%d AND `product_id`=%d ORDER BY `id` DESC", OrderStatus::TRADE_SUCCESS, $product_id);
    $results = $wpdb->get_col($sql);

    if(!$results || count($results) < 1) return null;


    $user_emails = $wpdb->get_col(sprintf("SELECT `user_email` FROM $wpdb->users WHERE ID IN (%s) AND $wpdb->users.user_email<>''", implode(',', $results)));

    set_transient($cache_key, maybe_serialize($user_emails), 3600*24);
    return $user_emails;
}