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Running Total of Orders
Finance wants a cumulative revenue line: for each order, the sum of that order and every order before it.
Show order_id, order_date, total, and running_total (cumulative sum by date, rounded to 2 decimals). Order by order_date, then order_id.
The new idea: add ORDER BY to a window aggregate. SUM(total) OVER (ORDER BY order_date, order_id) no longer sums the whole table — ordering the window makes SQL accumulate row by row, so each row sees everything up to and including itself. Same function as challenge 168, completely different meaning, and the only difference is the ORDER BY.
The last row's running_total equals the grand total. That's the quickest way to check your answer.
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Schema
orders
| order_id | customer_id | product | category | quantity | price | total | order_date | country | status |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | Laptop Pro | Electronics | 1 | 1299.99 | 1299.99 | 2024-01-15 | USA | completed |
| 2 | 2 | Wireless Mouse | Electronics | 2 | 49.99 | 99.98 | 2024-01-16 | Canada | completed |
| 3 | 3 | Office Chair | Furniture | 1 | 349.99 | 349.99 | 2024-01-17 | USA | completed |
Expected output: running_total 1299.99, 1399.97, 1749.96
Hint
SELECT, Window Functions, SUM, and open the hint there if you stall.Concepts
SELECT Window Functions SUM Running Total
Practise the topic: SQL practice questions · Window function practice · GROUP BY exercises
Read the concept: SQL running total
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