문제 출처.
GROUP BY
를 통해서 HOST_ID 별로 소유한 공간 수 체크HAVING
으로 2이상 조건 조회IN
)되는 HOST_ID만 출력SELECT * FROM PLACES AS PL1
WHERE PL1.HOST_ID IN (
SELECT HOST_ID FROM PLACES
GROUP BY HOST_ID
HAVING COUNT(*) >= 2
) ORDER BY ID;
GROUP BY
와 HAVING
으로 2개 이상 공간 소유 조회EXISTS
)하는지 체크SELECT * FROM PLACES AS PL1
WHERE EXISTS (
SELECT 1 FROM PLACES AS PL2
WHERE PL1.HOST_ID = PL2.HOST_ID
GROUP BY HOST_ID
HAVING COUNT(*) >= 2
) ORDER BY ID;