WorkBook

문제 답 1) IFNULL를 이용한 해결 SELECT PT_NAME, PT_NO, GEND_CD, AGE, IFNULL(TLNO, 'NONE') FROM PATIENT WHERE AGE

문제 답 나이 조건 1) 논리 연산자 해결 SELECT COUNT(USER_ID) FROM USER_INFO WHERE AGE >= 20 AND AGE = 20 AND AGE = 20 AND AGE

문제 답 1) IFNULL 를 이용한 풀이 SELECT WAREHOUSE_ID, WAREHOUSE_NAME, ADDRESS, ifnull(FREEZER_YN, 'N') AS FREEZER_YN FROM FOOD_WAREHOUSE WHERE ADDRESS LIKE '경기도%' ORDER BY WAREHOUSE_ID ASC 2) IF를 이용한 풀이 SELECT WAREHOUSE_ID, WAREHOUSE_NAME, ADDRESS, IF(FREEZER_YN IS NULL, 'N', FREEZER_YN) AS FREEZER_YN FROM FOOD_WAREHOUSE WHERE ADDRESS LIKE '경기도%' ORDER BY WAREHOUSE_ID ASC 3) COALESCE를 이용한 풀이 SELECT WAREH..

문제 답 1) 'SALES_DATE'의 조건을 DATE_FORMAT을 이용해 해결 SELECT DATE_FORMAT(SALES_DATE, '%Y-%m-%d') AS SALES_DATE, PRODUCT_ID, USER_ID, SALES_AMOUNT FROM ONLINE_SALE WHERE DATE_FORMAT(SALES_DATE, '%m') = '03' UNION SELECT DATE_FORMAT(SALES_DATE, '%Y-%m-%d') AS SALES_DATE, PRODUCT_ID, NULL AS USER_ID, SALES_AMOUNT FROM OFFLINE_SALE WHERE DATE_FORMAT(SALES_DATE, '%m') = '03' ORDER BY SALES_DATE, PRODUCT_ID, ..