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Introduction
Simple OVER()
PARTITION BY
Ranking functions
Window frame
19. Window frame – Summary
Analytic functions
ORDER BY PARTITION BY
Order of evaluation
Summary

## Instruction

Good job. Let's continue the adventure. In Part 5, we learned window frames. Let's take a look at the following example:

SELECT
id,
payment_date,
payment_amount,
SUM(payment_amount) OVER(
ORDER BY payment_date
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
FROM subscription;


In the above query, we calculate a running total paid for all subscriptions up to the current row.

## Exercise

For each single rental, show the id, rental_date, payment_amount and the running total of payment_amounts of all rentals from the oldest one (in terms of rental_date) until the current row.

### Stuck? Here's a hint!

Use ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW.