Window function

Applies to: sql

A window function computes across a set of rows related to the current row without collapsing them (unlike GROUP BY). With OVER (PARTITION BY ... ORDER BY ...) you get running totals, rankings, and moving averages while keeping every row.

SELECT day, sales,
       SUM(sales) OVER (ORDER BY day) AS running_total
FROM   daily;

See also: group-by, aggregate-function