-- 코드를 입력하세요
SELECT DATE_FORMAT(SALES_DATE, '%Y-%m-%d') as SALES_DATE, PRODUCT_ID, USER_ID, SALES_AMOUNT
FROM (
SELECT O.SALES_DATE, O.PRODUCT_ID, O.USER_ID, O.SALES_AMOUNT
FROM ONLINE_SALE O
WHERE O.SALES_DATE >= '2022-03-01' AND O.SALES_DATE <'2022-04-01'
UNION ALL
SELECT F.SALES_DATE, F.PRODUCT_ID, NULL as USER_ID, F.SALES_AMOUNT
FROM OFFLINE_SALE F
WHERE F.SALES_DATE >= '2022-03-01' AND F.SALES_DATE <'2022-04-01'
) AS S
ORDER BY SALES_DATE, PRODUCT_ID, USER_ID
SELECT vacation_id, emp_id, CONCAT_WS( ', ' , begin_data, end_date. reason,
duration) As info
FROM vacation;
ELT() - 나열된 값 중에서 지정한 위치의 값 변환
SELECT emp_name, emp_id, gender, dept_id, hire_date, salary,
ELT(NTILE(3) OVER(ORDER BY salary DESC), '상', '중', '하') AS grp
FROM employee
WHERE retire_date IS NULL AND salary IS NOT NULL;
FIELD
- 나열된 값 중에서 지정한 값이 있는 위치 반환, 없으면 0 반환
SELECT emp_name, emp_id, dept_id, hire_date, salary
FROM employee
WHERE dept_id IN ('MKT', 'SYS', 'HRD')
ORDER BY FIELD(dept_id, 'MKT', 'HRD', 'SYS');