Re: [HACKERS] DISTINCT and ORDER BY bug?

Don Baccus <dhogaza(at)pacifier(dot)com> writes:
> At 12:26 AM 2/7/00 -0500, Tom Lane wrote:
>> It would be interesting to poke at Oracle to find out just what they
>> consider a legitimate ORDER BY expression for a SELECT DISTINCT.

> I have full-time access to an Oracle installation, so fire away
> regarding examples and questions.

Well, try these on for size:

select distinct x from foo order by x+1;

select distinct x+1 from foo order by x+1;

select distinct x+1 from foo order by x;

select distinct x+1 from foo order by x+2;

select distinct x+y from foo order by x+y;

select distinct x,y from foo order by x+y;

select distinct x+y from foo order by x,y;

select distinct x+y from foo order by x-y;

A human can easily see that all but the last two are well-defined,
but I'll be a little surprised if Oracle knows it...

regards, tom lane