240811_TIL

아무리 사소하더라도 배움이 없는 날은 없다.

SQL 코드카타

문제 링크

SELECT person_id,
       Concat(name, Concat('(', LEFT(profession, 1), ')')) AS "name"
FROM   person
ORDER  BY 1 DESC;

문제 링크

SELECT emp_id,
       firstname,
       lastname,
       Max(salary) AS "salary",
       department_id
FROM   salary
GROUP  BY 1,
          2,
          3
ORDER  BY 1;

문제 링크

SELECT artist,
       Count(DISTINCT id) AS "occurrences"
FROM   spotify
GROUP  BY 1
ORDER  BY 2 DESC;

문제 링크
이 정도면 굉장히 친절한 문제다..

WITH total
     AS (SELECT order_date,
                Count(*) AS "cnt"
         FROM   delivery
         GROUP  BY 1),
     immed
     AS (SELECT order_date,
                Sum(CASE
                      WHEN order_date = customer_pref_delivery_date THEN 1
                      ELSE 0
                    END) AS "cnt_i"
         FROM   delivery
         GROUP  BY 1)
SELECT t.order_date,
       Round(100.0 * cnt_i / cnt, 2) AS "immediate_percentage"
FROM   total t
       LEFT JOIN immed i
              ON t.order_date = i.order_date
GROUP  BY 1
ORDER  BY 1;

문제 링크

SELECT bike_number,
       Max(end_time) AS "end_time"
FROM   bikes
GROUP  BY 1
ORDER  BY 2 DESC;

쉬운 문제들이 걸려서 5문제 빠르게 해결!
이제 최종 발표 준비하자🔥