Thanks, I was hoping there was some way to avoid it.
You have to write the subselect twice if you want to match up different
rows.
In some cases it might be worth making a copy in a temp table. For simple
subselects where there is an index on id, leaving it as is should work
fine.
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On Wed, Jan 26, 2005 at 23:12:25 +0100,
PFC <[EMAIL PROTECTED]> wrote:
>
> How do you do a self-join on a subselect ?
>
> like
> SELECT a.x+b.x FROM (subselect) a, (subselect) b WHERE a.id = b.id+10
>
> but without performing the subselect twice
>
It's not at all clear what you're asking. Do you have a real example,
preferably with EXPLAIN output?
On Wed, Jan 26, 2005 at 11:12:25PM +0100, PFC wrote:
>
> How do you do a self-join on a subselect ?
>
> like
> SELECT a.x+b.x FROM (subselect) a, (subselect) b WHERE a.id = b.i
How do you do a self-join on a subselect ?
like
SELECT a.x+b.x FROM (subselect) a, (subselect) b WHERE a.id = b.id+10
but without performing the subselect twice
..?
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