Re: contracting tables

"Peter T. Brown" <peter@memeticsystems.com> writes:
> I cannot seem to find the EXISTS keyword anywhere in the postgresql
> documentation.

Er ... um ... well ... there isn't any doco about EXISTS ... nor
related constructs such as IN.

I've attempted to rectify this in the 7.2-to-be docs, see
http://candle.pha.pa.us/main/writings/pgsql/sgml/functions-subquery.html
It's a tad on the dry-and-technical side, for sure.  You might prefer
to consult an introductory SQL book or three.
        regards, tom lane