Re: SQL question
- From: Jesper Haure Norrevang <jhn.aida@xxxxxx>
- To: geraldine_2@xxxxxxxxxxx
- Date: Fri, 03 Dec 2004 18:07:16 +0100
Geraldine,
select a, b
from mytable
where a <= b
union
select b, a
from mytable
where b = a
In Set Theory the set (1, 2) is equal to (2, 1).
Relational databases are (more and less) good implementations of Set Theory.
Basicly you are asking for a Set of Sets. Quite interesting. May be Lex has
some comments on this?
Regards
Jesper Haure
----- Original Message -----
From: geraldine_2@xxxxxxxxxxx
Date: Friday, December 3, 2004 5:37 pm
Subject: SQL question
> Hi,
> I have the following table below
>
> SQL> select * FRom mytable;
> A B
> ---------- ----------
> 1 2
> 3 4
> 2 1
> 5 6
> 4 3
>
> 5 rows selected.
>
> and I like to get the following output:
>
> A B
> ---------- ----------
> 1 2
> 3 4
> 5 6
>
>
> basically (1,2) is the same as (2,1) and I would just like to
> display any of those combination just once.
>
> Not sure how I can write a SQL to extract the data. Can someone help.
>
> TIA.
>
> Geraldine
> --
> //www.freelists.org/webpage/oracle-l
>
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