現在「xl_date」の日時変換に問題があり、日付は MM/DD/YYYY です
クエリ例:-
SELECT orders.*,
customer.id AS userid,
customer.login,
convert(datetime, orders.xl_date, 101) as ddates
FROM orders
LEFT JOIN customer
ON orders.userid = customers.id
WHERE 1
ORDER BY ddates DESC LIMIT 0, 30