[MySQL/프로그래머스] 오랜 기간 보호한 동물(1)

문제 설명

풀이

SELECT NAME, DATETIME
FROM (SELECT @ROWNUM := @ROWNUM+1 ROUNUM, A.*
        FROM ANIMAL_INS A LEFT OUTER JOIN ANIMAL_OUTS B ON A.ANIMAL_ID = B.ANIMAL_ID
        WHERE B.DATETIME IS NULL
        AND (@ROWNUM := 0) = 0
        ORDER BY DATETIME) D
WHERE D.ROUNUM <= 3