"Matthew Crouch" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Here's an easy one that I can't find laid out for me anywhere:
> I want a self join that pairs up the id numbers of a table in every
> permutation
>
> e.g. i have id #s 1, 2, and 3
> i need this result:
> 1 2
> 1 3
> 2 1
> 2 3
> 3 2
> 3 1
>
> clear enough?
Uh... haven't tested it, but seems likely:
SELECT a.id, b.id FROM mytable AS a JOIN mytable AS b ON a.id != b.id
1. this could easily return a very VERY
large result.
2. are {1,3} and {3,1} really different,
or should you use ...ON a.id < b.id ?
This would cut the size of your returned
query by half.
3. there are probably much better
means of accomplishing whatever you're
trying to do. Just getting the list of ids
and intersecting them in PHP sounds
like a better approach to me.
More information about what you're trying to
accomplish would help.
--
PHP Database Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
