SQL Window Functions: OVER Clause, PARTITION BY, ORDER BY, and Frames/Assign row numbers inside each partition
Number rows in order within each customer.
Section: OVER clause fundamentals
Assign row numbers inside each partition
sql
sql
SELECT order_id,
customer_id,
created_at,
ROW_NUMBER() OVER (
PARTITION BY customer_id
ORDER BY created_at DESC
) AS rn
FROM orders;Explanation
`ORDER BY` inside the window defines sequence for ranking and frame-aware calculations.
Learn the surrounding workflow
Compare similar commands or jump into common fixes when this command is part of a bigger troubleshooting path.
Related commands
Same sheet · prioritizing OVER clause fundamentals
Count all rows without collapsing them
Return total row count on every row.
Use RANGE for peer-aware frames
Group rows that share the same ordering value.
Exclude the current row from a frame
Compare a row against all earlier rows only.