SQL2

-- 최대 값
SELECT
    MAX(DATETIME) AS '시간'
FROM
    ANIMAL_INS;

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-- 최소 값 
SELECT
    MIN(DATETIME) AS '시간'
FROM
    ANIMAL_INS;

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-- 갯수 구하기
SELECT
    COUNT(*) AS count
FROM
    ANIMAL_INS;
    

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-- NULL과 중복되는 이름을 제거한 수를 셈.
SELECT
    COUNT(DISTINCT(NAME)) AS 'count'
FROM
    ANIMAL_INS
WHERE
    NAME IS NOT NULL;