Re: [HACKERS] subselect

Bruce Momjian <maillist@candle.pha.pa.us>

From: Bruce Momjian <maillist@candle.pha.pa.us>

To: lockhart@alumni.caltech.edu (Thomas G. Lockhart)

Cc: vadim@sable.krasnoyarsk.su, hackers@postgreSQL.org

Date: 1998-01-06T05:06:39Z

Lists: pgsql-hackers

> 
> > BTW, note that for _expression_ subqueries (which are introduced without
> > IN, EXISTS, ALL, ANY - this follows Sybase' naming) - as in your examples -
> > we have to check that subquery returns single tuple...
> 
> It might be nice to have a tuple-counting operation or query node (is this the right
> terminology?) which could be used to help implement EXISTS. It might help to
> re-implement the count(*) function also.

In the new code, count(*) picks a column from one of the tables to count
on.


-- 
Bruce Momjian
maillist@candle.pha.pa.us