인프런 커뮤니티 질문&답변

1. ARRAY, STRUCT

1) array_exercises 테이블에서 각 영화(title)별로 장르(genres)를 UNNEST해서 보여주세요

SELECT 
  title, 
  -- genres,
  genre
FROM advanced.array_exercises AS ae
CROSS JOIN UNNEST(genres) AS genre

2) array_exercises테이블에서 각 영화(title)별로 배우(actor)와 배역(character)을 보여주세요.배우와 배역은 별도의 컬럼으로 나와야합니다

SELECT 
  title,
  actor.actor,
  actor.character
  -- actors,
  -- actors[SAFE_OFFSET(0)].actor AS actor,
  -- actors[SAFE_OFFSET(1)].character AS character 
FROM advanced.array_exercises
CROSS JOIN UNNEST(actors) AS actor

3) array_exercises 테이블에서 각 영화(title)별로 배우(actor), 배역(character), 장르(genre)를 출력하세요. 한 Row에 배우,배역,장르가 모두 표시 되어야 합니다

SELECT 
  title, 
  -- actors, 
  actor.actor,
  actor.character,
  genre
FROM advanced.array_exercises
CROSS JOIN UNNEST(actors) AS actor
CROSS JOIN UNNEST(genres) AS genre

4) 앱 로그 데이터(app_logs)의 배열을 풀어주세요

SELECT 
  user_id,
  event_date, 
  event_name, 
  user_pseudo_id,
  event_param.key AS key,
  -- event_param.value AS value,
  event_param.value.string_value AS string_value,
  event_param.value.int_value AS int_value
FROM advanced.app_logs
CROSS JOIN UNNEST(event_params) AS event_param
WHERE event_date = '2022-08-01'

2. PIVOT

1) orders 테이블에서 유저(user_id)별로 주문 금액(amount)의 합계를 PIVOT해주세요. 날짜(order_date)를 행(Row)으로, user_id를 열(Column)으로 만들어야 합니다


SELECT 
  order_date,
  SUM(IF(user_id = 1, sum_of_amount, 0)) AS user_1,
  SUM(IF(user_id = 2, sum_of_amount, 0)) AS user_2,
  SUM(IF(user_id = 3, sum_of_amount, 0)) AS user_3
FROM 
  (SELECT 
    order_date,
    user_id,
    SUM(amount) as sum_of_amount
  FROM advanced.orders
  GROUP BY 
    order_date, user_id
  )
GROUP BY order_date
ORDER BY order_date

SELECT 
  order_date,
  SUM(IF(user_id = 1, amount, 0)) AS user_1,
  SUM(IF(user_id = 2, amount, 0)) AS user_2,
  SUM(IF(user_id = 3, amount, 0)) AS user_3
FROM 
  advanced.orders
GROUP BY order_date
ORDER BY order_date


 2) orders 테이블에서 날짜(order_date)별로 유저들의 주문 금액(amount)의 합계를 PIVOT 해주세요. user_id를 행(Row)으로, order_date를 열(Column)으로 만들어야 합니다
SELECT 
  user_id,
  SUM(IF(order_date = '2023-05-01', amount, 0)) AS `2023-05-01`,
  SUM(IF(order_date = '2023-05-02', amount, 0)) AS `2023-05-02`,
  SUM(IF(order_date = '2023-05-03', amount, 0)) AS `2023-05-03`,
  SUM(IF(order_date = '2023-05-04', amount, 0)) AS `2023-05-04`,
  SUM(IF(order_date = '2023-05-05', amount, 0)) AS `2023-05-05`
FROM 
  advanced.orders
GROUP BY   user_id
ORDER BY   user_id



3) orders 테이블에서 사용자(user_id)별, 날짜(order_date)별로 주문이 있다면 1, 없다면 0으로 PIVOT 해주세요. user_id를 행(Row)으로, order_date를 열(Column)로 만들고 주문을 많이 해도 1로 처리합니다


SELECT 
  user_id,
  MAX(IF(order_date = '2023-05-01', 1, 0)) AS `2023-05-01`,
  MAX(IF(order_date = '2023-05-02', 1, 0)) AS `2023-05-02`,
  MAX(IF(order_date = '2023-05-03', 1, 0)) AS `2023-05-03`,
  MAX(IF(order_date = '2023-05-04', 1, 0)) AS `2023-05-04`,
  MAX(IF(order_date = '2023-05-05', 1, 0)) AS `2023-05-05`
FROM 
  advanced.orders
GROUP BY   user_id
ORDER BY   user_id



4) user_id = 32888이 카트 추가하기(click_cart)를 누를때 어떤 음식(food_id)을 담았나요?
SELECT 
  event_date, 
  event_timestamp,
  event_name, 
  user_id,
  user_pseudo_id,
  MAX(IF(param.key = 'firebase_screen', param.value.string_value, null)) AS firebase_screen,
  MAX(IF(param.key = 'food_id', param.value.int_value, null)) AS food_id
FROM advanced.app_logs
CROSS JOIN UNNEST(event_params) AS param
WHERE 
  user_id = 32888
  and event_name = 'click_cart'
GROUP BY ALL
ORDER BY event_date 

3. 퍼널

WITH base AS (
  SELECT
    event_date,
    event_timestamp,
    event_name,
    user_id,
    user_pseudo_id,
    platform,
    -- event_param
    MAX(IF(event_param.key = "firebase_screen", event_param.value.string_value, NULL)) AS firebase_screen,
    -- MAX(IF(event_param.key = "food_id", event_param.value.int_value, NULL)) AS food_id,
    MAX(IF(event_param.key = "session_id", event_param.value.string_value, NULL)) AS session_id
  FROM advanced.app_logs
  CROSS JOIN UNNEST(event_params) AS event_param
  WHERE
    -- event_date = "2022-08-01" # 적은 데이터로 쿼리를 작성하기 위해 만들어둔 조건
    event_date BETWEEN "2022-08-01" AND "2022-08-18"
  GROUP BY ALL
), filter_event_and_concat_event_and_screen AS (
  -- (1) event_name + screen (필요한 이벤트만 WHERE 조건에 걸어서 사용)
  SELECT
    * EXCEPT(event_name, firebase_screen, event_timestamp),
    CONCAT(event_name, "-", firebase_screen) AS event_name_with_screen,
    DATETIME(TIMESTAMP_MICROS(event_timestamp), 'Asia/Seoul') AS event_datetime
  FROM base
  WHERE
    event_name IN ("screen_view", "click_payment")
), 
funnel AS (
  SELECT
    event_date,
    event_name_with_screen,
    CASE 
      WHEN event_name_with_screen = "screen_view-welcome" THEN 1
      WHEN event_name_with_screen = "screen_view-home" THEN 2
      WHEN event_name_with_screen = "screen_view-food_category" THEN 3
      WHEN event_name_with_screen = "screen_view-restaurant" THEN 4
      WHEN event_name_with_screen = "screen_view-cart" THEN 5
      WHEN event_name_with_screen = "click_payment-cart" THEN 6
    ELSE NULL
    END AS step_number,
    COUNT(DISTINCT user_pseudo_id) AS cnt
  FROM filter_event_and_concat_event_and_screen
  GROUP BY ALL
  HAVING step_number IS NOT NULL
  )

SELECT 
  event_date,
  MAX(IF(funnel.event_name_with_screen = 'screen_view-welcome', cnt, null)) as `screen_view-welcome`,
  MAX(IF(funnel.event_name_with_screen = 'screen_view-home', cnt, null)) as `screen_view-home`,
  MAX(IF(funnel.event_name_with_screen = 'screen_view-food_category', cnt, null)) as `screen_view-food_category`,
  MAX(IF(funnel.event_name_with_screen = 'screen_view-restaurant', cnt, null)) as `screen_view-restaurant`,
  MAX(IF(funnel.event_name_with_screen = 'screen_view-cart', cnt, null)) as `screen_view-cart`,
  MAX(IF(funnel.event_name_with_screen = 'click_payment-cart', cnt, null)) as `click_payment-cart`
FROM funnel 
GROUP BY ALL
ORDER BY event_date