Window Functions
Named Windows: The WINDOW Clause
Senior Data Analyst
March 10, 2026
4 min read
DRY: Don't Repeat Yourself
If you're using the same `OVER (PARTITION BY ... ORDER BY ...)` clause multiple times, you can name it.
The WINDOW Clause
SELECT
customer_id, order_date, amount,
SUM(amount) OVER w AS running_total,
AVG(amount) OVER w AS running_avg,
ROW_NUMBER() OVER w AS order_seq
FROM orders
WINDOW w AS (PARTITION BY customer_id ORDER BY order_date);
Pro Tip
This makes your SQL cleaner and easier to modify. Change the window definition in one place instead of many.
*Day 70: Window Functions vs. GROUP BY.*