The big idea behind window functions is to allow you to process several values of the result set at a time. you see through the window some peer rows and are able to compute a single output value from them, much like when using an aggregate function.
When looking through a window we only see a frame at a time. Its all about the frame. The gadget spec URL could not be found sachi=# select region, rank() over (W) from sachi.sales WINDOW W as (order by year); region | rank --------+------ asia | 1 usa | 2 (2 rows) The gadget spec URL could not be found The gadget spec URL could not be found | The gadget spec URL could not be found |
