꿈라CBT다음 SQL의 결과로 가장 적절한 것은 무엇인가?
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[SALES]
| SALE_DATE | AMT |
|---|---|
| 2026-01-01 | 100 |
| 2026-01-02 | 150 |
| 2026-01-03 | 120 |
SELECT SALE_DATE, AMT, AMT - LAG(AMT) OVER(ORDER BY SALE_DATE) AS DIFF FROM SALES;
- 1
SALE_DATE AMT DIFF 01-01 100 NULL 01-02 150 50 01-03 120 -30 - 2
SALE_DATE AMT DIFF 01-01 100 0 01-02 150 50 01-03 120 -30 - 3
SALE_DATE AMT DIFF 01-01 100 NULL 01-02 150 150 01-03 120 120 - 4
SALE_DATE AMT DIFF 01-01 100 100 01-02 150 50 01-03 120 -30