SELECT d, rnk, NTILE(10) OVER (PARTITION BY d, category ORDER BY rnk) AS bucket, sales, category, sub_category, goods_id
FROM
(
  SELECT
    d, RANK() OVER (PARTITION BY d, category ORDER BY sales DESC) AS rnk, sales, category, sub_category, goods_id
  FROM
  (
    SELECT category, sub_category, goods_id, SUM(price*amount) AS sales, TD_TIME_FORMAT(time, 'yyyy-MM-01', 'JST') AS d
    FROM sales_slip
    WHERE TD_TIME_RANGE(time, '2013-01-01', '2013-04-01', 'JST')
    GROUP BY category, sub_category, goods_id, TD_TIME_FORMAT(time, 'yyyy-MM-01', 'JST')
  ) t1
) t2
WHERE rnk <= 100
ORDER BY d, category, rnk, bucket