Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!swrinde!mips!pacbell.com!pacbell!rtech!ingres!ingres.com!billc
From: billc@ingres.com (Bill Coffin, x3387)
Newsgroups: comp.databases
Subject: Re: Bizarre Database Reporting
Message-ID: <1991May15.173012.1548@ingres.Ingres.COM>
Date: 15 May 91 17:30:11 GMT
References: <1991May13.162936.14729@hellgate.utah.edu>
Lines: 26

From article <1991May13.162936.14729@hellgate.utah.edu>, by knechod%peruvian.utah.edu@cs.utah.edu (Kevin Nechodom):
> Here is a question that I have used to harass the database companies
> that bring in their "Wonderful World of Our Database" shows.  This is just
> a base case; any response to this question will quite likely inspire a flurry
> of counter-questions.  Anyway...

Sounds like you're out for blood.
 
Anyway, here's a quick knockoff on Ingres.  It requires some "dictionary" support, but
I'd be surprised to find an RDBMS that didn't have a table describing table columns.

    select i.id, c.column_name
	from iemps i, iicolumns c
	where c.table_name='iemps'
	and (
		(c.column_name = 'name' and i.name is null)
		or (c.column_name = 'dept' and i.dept is null)
		or (c.column_name = 'salary' and i.salary is null)
	)

You could easily write a little tool that would generate this query automatically, just by
feeding it a table name.
--

Bill Coffin, aka billc@ingres.com 
 FETCH INTO :standard_disclaimer, :gratuitous_witticism, :obscure_quote