I have this query currently, which selects the top "number of pickups" in descending order. I need to filter only the top 10 rows/highest numbers though. How can I do this? 

I have tried adding 'WHERE ROWNUM <= 10' at the bottom, to no avail.

```
SELECT customer.company_name, COUNT (item.pickup_reference) as "Number of Pickups" 
FROM customer
JOIN item ON (customer.reference_no=item.pickup_reference) 
GROUP BY customer.company_name, item.pickup_reference
ORDER BY COUNT (customer.company_name) DESC;

```

Thanks for any help!