분기별 분화된 대장균의 개체 수 구하기

-- MONTH() 
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