[SQL] 오프라인/온라인 판매 데이터 통합하기

https://school.programmers.co.kr/learn/courses/30/lessons/131537

My Answer

SELECT TO_CHAR(SALES_DATE,'YYYY-MM-DD') AS SALES_DATE, PRODUCT_ID, USER_ID, SALES_AMOUNT
FROM ONLINE_SALE
WHERE TO_CHAR(SALES_DATE, 'YYYYMM') = '202203'

UNION ALL

SELECT TO_CHAR(SALES_DATE,'YYYY-MM-DD') AS SALES_DATE, PRODUCT_ID, NULL AS USER_ID, SALES_AMOUNT
FROM OFFLINE_SALE
WHERE TO_CHAR(SALES_DATE, 'YYYYMM') = '202203'
ORDER BY SALES_DATE, PRODUCT_ID, USER_ID