Re: [HACKERS] Re: [SQL] DISTINCT ON: speak now or forever hold your peace

> (BTW, ordinary SELECT DISTINCT has this same sort of problem if you try
> to ORDER BY an expression that doesn't appear in the target list.
> SQL92 avoids the issue by not allowing you to ORDER BY expressions that
> aren't in the target list, period.  We do allow that --- but not when
> you use DISTINCT.  Essentially, I want to enforce that same restriction
> for DISTINCT ON.)
> 
> The other piece of the puzzle would be to document that DISTINCT ON
> keeps the first tuple out of each set with the same DISTINCT ON value.
> 
> Does that sound like a plan?

Yes, very clear.  Good.

--  Bruce Momjian                        |  http://www.op.net/~candle pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026