给出一个列 OrderID,CustomerID,OrderDate和OrderAmount的订单表,写一个SQL查询,查找过去一个月花费最多钱的前3名客户,其中过去一个月被定义为当前日期前30天.
Here's an example SQL query that should work:

```SQL
SELECT CustomerID, SUM(OrderAmount) as TotalSpent
FROM orders
WHERE OrderDate >= DATEADD(day, -30, GETDATE())
GROUP BY CustomerID
ORDER BY TotalSpent DESC
LIMIT 3;
```