You can think of
window_function() over (partition by A,B,C [order by C,D,E])
as
'Within each group of records with a common A+B+C, return window_function [as if the rows were ordered by C,D,E] but don't group or sort the actual result rows in those ways'
I always mistakenly start by thinking that there is one window function result per A+B+C combination. There is not, there is one result per original query row.
In particular, the order by C,D,E here is an ordering of the original query rows within each group.
Anti-nuisance lawsuit warning: The purpose of these notes is to remind me, Zoegond, of stuff or to help me work stuff out. They may contain mistakes.
Quick
- ($a, $b....) = unpack("A2A7...", $packed)
- push( array, list )
