[PGS] 경기도에 위치한 식품창고 목록 출력하기

문제

예제

내 풀이

SELECT WAREHOUSE_ID, WAREHOUSE_NAME, ADDRESS, NVL(FREEZER_YN, 'N')
FROM FOOD_WAREHOUSE
WHERE SUBSTR(ADDRESS, 1, 3) = '경기도'
ORDER BY WAREHOUSE_ID;

SELECT WAREHOUSE_ID, WAREHOUSE_NAME, ADDRESS, NVL2(FREEZER_YN,FREEZER_YN, 'N') AS FREEZER_YN
FROM FOOD_WAREHOUSE
WHERE SUBSTR(ADDRESS, 1, 3) = '경기도'
ORDER BY WAREHOUSE_ID;

정리

NVL(A, B) = A가 NULL 이면 B
NVL2(A, B, C) = A가 NULL이 아니면 B, NULL 이면 C