[26.03.05 코테(MySQL)]-분기별 분화된 대장균의 개체 수 구하기

Lv2. 분기별 분화된 대장균의 개체 수 구하기 (MySQL)

링크: https://school.programmers.co.kr/learn/courses/30/lessons/299308

 

내가 작성한 코드

-- 풀이1
SELECT CONCAT(QUARTER(DIFFERENTIATION_DATE), 'Q') AS QUARTER
       ,COUNT(*) AS ECOLI_COUNT
FROM ECOLI_DATA
GROUP BY QUARTER
ORDER BY QUARTER;

-- 풀이2
SELECT CASE WHEN MONTH(DIFFERENTIATION_DATE) BETWEEN 1 AND 3 THEN '1Q'
            WHEN MONTH(DIFFERENTIATION_DATE) BETWEEN 4 AND 6 THEN '2Q'
            WHEN MONTH(DIFFERENTIATION_DATE) BETWEEN 7 AND 9 THEN '3Q'
            WHEN MONTH(DIFFERENTIATION_DATE) BETWEEN 10 AND 12 THEN '4Q'
            END AS QUARTER
            ,COUNT(*) AS ECOLI_COUNT
FROM ECOLI_DATA
GROUP BY QUARTER
ORDER BY QUARTER;

 

문자열을 합쳐주는 CONCAT 함수