Re: Self-Referencing

On Wed, 28 Mar 2001, David Olbersen wrote:

> Hello,
> 
>   I have a feeling this isn't going to make much sense, but I'm gonig to try
>   anyway.
> 
>   What I'd like to do is be able to refer to an outer-SELECT from an
>   inner-SELECT. I hope this makes sense.
> 
>   I need to be able to refer to the row that's being processed in a SELECT. I'm
>   going to use the idea of 'this' referring to the row that's currently being
>   processed. Here's the example of what I'd like:
> 
>   SELECT
>     building_id,
>     num_buildings,
>     (
>       SELECT count( building_id )
>       FROM   building_portals
>       WHERE  building_id = THIS.building_id
>     )
>   FROM buildings;
> 
>   Am I making things too complicated, and if so will somebody *PLEASE* tell me
>   the easier way to do this. Thanks.
> 
> -- Dave

If I understand what you're trying to do, try this:
 SELECT   building_id,   num_buildings,   (     SELECT count( building_id )     FROM   building_portals     WHERE
building_id= THIS.building_id   ) FROM buildings AS THIS;              __^^^^^^^                 
 
You might also want to add in a 'AS num_portals' after the sub-select.

-Cedar