When in doubt, cheat! Why not something like: SELECT x, y FROM organ_pipes WHERE point(x,y) <@ box(point(?x1,?y1),point(?x2,?y2)) ;
This is definitely a different approach from the others that I've seen. Basically, think of your channel / piston as a point in a Cartesian plane. And your boundaries as a box in that graph. So you see if the "point" is inside the "box" On Mon, Oct 5, 2015 at 1:39 PM, Raymond O'Donnell <r...@iol.ie> wrote: > Hello all, > > I have an SQL problem which ought to be simple, but I can't get my head > around it. > > I have pairs of integers - let's call them (x, y). In effect, x is a > category, while y is an item within that category. For every x, there is > always the same number of integers y; and both x and y are always > numbered sequentially starting from 1. > > My problem is that I need to select a list of these pairs, ordered first > on x and then on y, from a given starting point to a given finishing > point and including all pairs in between. > > For example, I might have: > > x | y > ----- > 1 | 1 > 1 | 2 > 1 | 3 > 1 | 4 > 2 | 1 > 2 | 2 > 2 | 3 > 2 | 4 > (etc) > > I then might want to extract a list from, say, (1, 3) to (3, 2), giving: > > x | y > ----- > 1 | 3 > 1 | 4 > 2 | 1 > 2 | 2 > 2 | 3 > 2 | 4 > 3 | 1 > 3 | 2 > > For the life of me, I can't figure out how to do this. Any help will be > appreciated, or even just a pointer in the right direction. There's > probably something simple that I'm just not seeing.... > > If anyone's interested, these numbers represent channels and pistons on > the combination system of a largish pipe organ... it's for a hobby project. > > Many thanks in advance! > > Ray. > > > -- > Raymond O'Donnell :: Galway :: Ireland > r...@iol.ie > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general > -- Schrodinger's backup: The condition of any backup is unknown until a restore is attempted. Yoda of Borg, we are. Futile, resistance is, yes. Assimilated, you will be. He's about as useful as a wax frying pan. 10 to the 12th power microphones = 1 Megaphone Maranatha! <>< John McKown
