SQLD(SQL 개발자) 기출 · 서브쿼리

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1. 1.SELECT CODE, NAME, (SELECT PRICE FROM PRODUCT WHERE P1.CODE = P2.CODE) FROM PRODUCT P1;
2. 2.SELECT CODE, NAME, PRICE FROM PRODUCT P1 WHERE PRICE = (SELECT MAX(PRICE) FROM PRODUCT P2 WHERE P1.CODE = P2.CODE);
3. 3.SELECT CODE, NAME, PRICE FROM PRODUCT WHERE (CODE, PRICE) IN (SELECT CODE, MAX(PRICE) FROM PRODUCT GROUP BY CODE);
4. 4.SELECT P.CODE, P.NAME, P.PRICE FROM PRODUCT P, (SELECT CODE, MAX(PRICE) AS MAX_PRICE FROM PRODUCT GROUP BY CODE) I WHERE P.CODE = I.CODE AND P.PRICE = I.MAX_PRICE;