지역별 주문의 특징 *pivot table

--https://solvesql.com/problems/characteristics-of-orders/
--creating pivot table in MYSQL
SELECT
  REGION as "Region",
  COUNT(DISTINCT CASE WHEN CATEGORY = "Furniture" THEN order_id END) AS Furniture,
  COUNT(DISTINCT CASE WHEN CATEGORY =  "Office Supplies" THEN order_id END) AS "Office Supplies",
  COUNT(DISTINCT CASE WHEN CATEGORY =  "Technology" THEN order_id END) AS Technology
FROM
  records
GROUP BY
  REGION
ORDER BY
  REGION ASC;