您可以使用此处描述的 rank() UDF 来实现:http://ragrawal.wordpress.com/2011/11/18/extract-top-n-records-in-each-group-in-hadoophive/

You can do it with a rank() UDF described here: http://ragrawal.wordpress.com/2011/11/18/extract-top-n-records-in-each-group-in-hadoophive/

SELECT page-id, user-id, clicks
FROM (
    SELECT page-id, user-id, rank(user-id) as rank, clicks
    FROM mytable
    DISTRIBUTE BY page-id, user-id
    SORT BY page-id, user-id, clicks desc
) a 
WHERE rank < 5
ORDER BY page-id, rank