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From: doug@bear.cis.ohio-state.edu (Doug Kerr)
Newsgroups: comp.databases
Subject: SQL question
Message-ID: <75547@tut.cis.ohio-state.edu>
Date: 11 Jan 90 16:01:51 GMT
Sender: news@tut.cis.ohio-state.edu
Reply-To: Doug Kerr <doug@cis.ohio-state.edu>
Organization: Ohio State University Computer and Information Science
Lines: 27


I'm trying to write a single SELECT statement that involves a complex
sort order and have had no success.  The problem is given a relation
	R(A,B,C,D)
sort as follows:

    all tuples with A > A1, 			sorted by A
    all tuples with A <= A1 and B > B1,		sorted by B
    all other tuples (A <= A1  &  B <= B1),	sorted by C

I can write seperate SELECTS for each subset, but is there a way to
combine the three sets into one?  I need this ordering because I need
to make assignments in an embeded SQL program corresponding to the D
values based on the ranking given by this sort order, i.e. I may
assign one value to the first 10 D's, another value to the next 20
values, etc.  There is no relationship between 10, 20, etc. and the
breaks in the three groups.  The program will be much easier to write
if I need one cursor rather than 3.

Thanks for any help you can provide.


-=-
 Douglas S. Kerr, Department of Computer and Information Science
 The Ohio State University; 2036 Neil Ave. Columbus OH USA 43210-1277
 doug@cis.ohio-state.edu                    614/292-1519
 ...!{pyramid,killer}!osu-cis!cis.ohio-state.edu!doug