-----Original Message----- From: pgsql-general-ow...@postgresql.org [mailto:pgsql-general-ow...@postgresql.org] On Behalf Of Raymond O'Donnell Sent: Monday, October 05, 2015 2:40 PM To: 'PostgreSQL' <pgsql-general@postgresql.org> Subject: [GENERAL] Selecting pairs of numbers
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. ____________________________________ SELECT x, y FROM my_table WHERE (x*10 + y) >= (1*10 + 3) AND (x*10 + y) <= (3*10 + 2) ORDER BY x, y; Regards, Igor Neyman -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
