Re: Selecting pairs of numbers - Mailing list pgsql-general

From Chris Mair
Subject Re: Selecting pairs of numbers
Date
Msg-id bb61f220a0ba4aa1c42740957772ab0b@smtp.hushmail.com
Whole thread Raw
In response to Selecting pairs of numbers  (Raymond O'Donnell <rod@iol.ie>)
List pgsql-general
> 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.

Hi,

starting from this:


chris=# select * from t order by x,y;
  x | y
---+---
  1 | 1
  1 | 2
  1 | 3
  1 | 4
  2 | 1
  2 | 2
  2 | 3
  2 | 4
  3 | 1
  3 | 2
  3 | 3
  3 | 4
(12 rows)

one trick that might help is this:

chris=# select * from t where x*1000+y >= 1003 and x*1000+y <= 3002 order by x,y;
  x | y
---+---
  1 | 3
  1 | 4
  2 | 1
  2 | 2
  2 | 3
  2 | 4
  3 | 1
  3 | 2
(8 rows)

watch out, if you have y values bigger than 1000, though...


Bye,
chris.






pgsql-general by date:

Previous
From: Karsten Hilbert
Date:
Subject: Re: md5(large_object_id)
Next
From: Adrian Klaver
Date:
Subject: Re: Selecting pairs of numbers