Here is an example SQL query to retrieve the top 5 customers who have spent the most money:

```
SELECT CustomerID, SUM(OrderAmount) as TotalSpent
FROM customer_orders
GROUP BY CustomerID
ORDER BY TotalSpent DESC
LIMIT 5;
```

This query uses the `SUM` aggregate function to calculate the total amount spent by each customer, `GROUP BY` to group the results by customer, `ORDER BY` to sort the results by total spent in descending order, and `LIMIT` to restrict the output to the top 5 customers.
Data una tabella di ordini cliente con colonne CustomerID, OrderID, OrderDate e OrderAmount, scrivi una query SQL per trovare i primi 5 clienti che hanno speso di più.