[해커랭크]Occupations

문제

https://www.hackerrank.com/challenges/occupations/problem?isFullScreen=true
1. 직업을 열로 가져오는 피봇 문제!

풀이

SELECT
        MAX(CASE WHEN Occupation ='Doctor' THEN Name END),
        MAX(CASE WHEN Occupation ='Professor' THEN Name END),
        MAX(CASE WHEN Occupation ='Singer' THEN Name END),
        MAX(CASE WHEN Occupation ='Actor' THEN Name END)
FROM(
    SELECT *,
        ROW_NUMBER() OVER(PARTITION BY Occupation ORDER BY Name) AS num
    FROM
        OCCUPATIONS) num_occ 
GROUP BY
    num_occ.num

후기

아.. 집계 함수 쓰는 부분이 너무 헷갈린다 대체 왜쓰는걸까!!!