첫 주문과 마지막 주문 & 가구 판매의 비중이 높았던 날 찾기 (solvesql)

첫 주문과 마지막 주문

https://solvesql.com/problems/first-and-last-orders/
MIN() 함수와 MAX() 함수를 이용해서 첫 주문과 마지막 주문 데이터를 조회합니다.

SELECT
  MIN(DATE_FORMAT(order_purchase_timestamp, '%Y-%m-%d')) AS first_order_date,
  MAX(DATE_FORMAT(order_purchase_timestamp, '%Y-%m-%d')) AS last_order_date
FROM
  olist_orders_dataset

가구 판매의 비중이 높았던 날 찾기

https://solvesql.com/problems/day-of-furniture/

SELECT
  order_date,
  COUNT(DISTINCT IF(category = 'Furniture', order_id, NULL)) AS furniture,
  ROUND(
    COUNT(
      DISTINCT CASE
        WHEN category = 'Furniture' THEN order_id
      END
    ) * 100 / COUNT(DISTINCT order_id),
    2
  ) AS furniture_pct
FROM
  records
GROUP BY
  order_date
HAVING
  COUNT(DISTINCT order_id) >= 10
  AND furniture_pct >= 40
ORDER BY
  furniture_pct DESC,
  order_date