Compute Cumulative Running Totals with SUM() OVER in SQL

Question

Given `daily_sales` (sale_date, daily_amount), write a SQL query to calculate the cumulative running total of revenue up to each day.

Accepted Answer

Optimal Solution:
SELECT 
  sale_date,
  daily_amount,
  SUM(daily_amount) OVER (
    ORDER BY sale_date ASC 
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
  ) AS running_total
FROM daily_sales
ORDER BY sale_date ASC;

Technical Explanation:
The window clause `ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW` accumulates sums from the first record up to the current row.

sale_date	daily_amount
2026-01-01	1000
2026-01-02	1500
2026-01-03	2000

sale_date	daily_amount	running_total
2026-01-01	1000	1000
2026-01-02	1500	2500
2026-01-03	2000	4500