Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!usc!ucsd!ogicse!milton!ejbell@milton.u.washington.edu
From: ejbell@milton.u.washington.edu (Eric Bell)
Newsgroups: comp.databases
Subject: SQL, using IN with multi-column keys
Message-ID: <6410@milton.u.washington.edu>
Date: 16 Aug 90 18:25:34 GMT
Sender: ejbell@milton.u.washington.edu
Distribution: usa
Organization: University of Washington, Seattle
Lines: 26

SQL allows you to easily determine if a single value is in a list.  For
example:

	select * 
	from data
	where data.cnum in (select cnun from list);

This is great if cnum is the key for the 'data' table.  But what do you
do if the key is comprised of multiple columns?  Can you do something like:

	select *
	from data
	where {data.cnum,data.cic} in (select cnum,cic from list);

Or do you have to do a join?  It seems like this would come up over and over
again, and I'm surprised that SQL doesn't support looking up a tuple in a list.

Or am I wrong?

Eric Julian Bell
Business Administration Computer Services, DJ-10
University of Washington
Seattle, WA  98195

(206)543-7125
ejbell@byron.u.washington.edu