[Programmers] 연도 별 평균 미세먼지 농도 조회하기

문제 링크

정답

-- AIR_POLLUTION: LOCATION1, LOCATION2, YM, PM_VAL1, PM_VAL2

SELECT 
    YEAR(YM) AS 'YEAR', 
    ROUND(AVG(PM_VAL1), 2) AS 'PM10', 
    ROUND(AVG(PM_VAL2), 2) AS 'PM2.5'
FROM AIR_POLLUTION
WHERE (LOCATION1 = '경기도' AND LOCATION2 = '수원')
GROUP BY YEAR(YM)
ORDER BY 1;

✅ Point

• WHERE > GROUP 순으로
• ROUND 로 반올림