Re: [HACKERS] Oops, I seem to have changed UNION's behavior

> Thomas Lockhart <lockhart(at)alumni(dot)caltech(dot)edu> writes:
> >>>> Am I right in thinking that UNION (without ALL) is defined to do a
> >>>> DISTINCT on its result, so that duplicates are removed even if the
> >>>> duplicates both came from the same source table? That's what 6.4.2
> >>>> does, but I do not know if it's strictly kosher according to the SQL
> >>>> spec.
>
> > (Just in case this is still active)
>
> > Yes, this is the right behavior according to SQL92...
>
> OK, then 6.5 is still broken :-(. I know a lot more about the planner
> than I did then, so I will see if I can fix it "right" --- that is,
> without taking out equal()'s ability to detect equality of Query nodes.
>
> If that seems too hard/risky, I will just lobotomize equal() instead.
>
> Thanks for the reminder, Bruce --- I had forgotten about this issue.

Hey, that's why I keep 500 messages in my PostgreSQL mailbox.

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