Introduction
PARTITION BY
Ranking functions
Window frame
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.
