Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
Home -> Community -> Mailing Lists -> Oracle-L -> Re: SQL question
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
> 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
> --
> http://www.freelists.org/webpage/oracle-l
>
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Dec 03 2004 - 11:06:07 CST