An e-commerce analyst wants to compare each day’s sales to t…
An e-commerce analyst wants to compare each day’s sales to the previous day’s sales in order to spot drops in performance. Which SQL window function is best suited for this? OPTIONS:A. SUM OVER (PARTITION BY day)B. LAG with ORDER BY sale_dateC. LEAD with ORDER BY sale_dateD. ROW_NUMBER with PARTITION BY sale_date ANSWER:B EXPLANATION:LAG allows access to the previous row’s value when ordered by date, which is exactly what the analyst needs. LEAD looks forward (C), SUM aggregates without comparing rows (A), and ROW_NUMBER just assigns sequence numbers (D).