I have a simple view in my MSSQL database. It consists of the following fields:

report_id INT
ym VARCHAR -- YYYY-MM
keyword VARCHAR(MAX)
visits INT

I can easily get the top 10 keyword hits with the following query:

SELECT TOP 10 *
FROM top_keywords
WHERE ym BETWEEN '2010-05' AND '2010-05'
ORDER BY visits DESC

Now where it gets tricky is where I have to get the top 10 records for each report_id in the given date range (ym BETWEEN @start_date AND @end_date).

How would I go about getting the top 10 for each report_id? I've stumbled across suggestions involving the use of ROW_NUMBER() and RANK(), but have been vastly unsuccessful in their implementation.