Re: Subselects open issue Nr. NEW - Mailing list pgsql-hackers

From Zeugswetter Andreas SARZ
Subject Re: Subselects open issue Nr. NEW
Date
Msg-id 219F68D65015D011A8E000006F8590C6010A51DC@sdexcsrv1.sd.spardat.at
Whole thread Raw
In response to Subselects open issue Nr. NEW  ("Vadim B. Mikheev" <vadim@sable.krasnoyarsk.su>)
List pgsql-hackers
Sorry, I take back my gordian knot, I found it in my own brains ;-(
For a <=, <, >=, > a lexical ordering would be more intuitive,
since that is how a compound index would sort.

so (a, b) <= (c, d) would resolve to:
(a <= c) or ((a = c) and (b <= c))

What happens to !=~ ? Should also be _OR_ ed.
I guess that leaves us at a point of no go. Take it out ? *tear drops
falling*

Andreas

> Vectors cannot be strictly ordered.  "Partial orderings" are possible.

I think it should say: an order has to be defined (lexical, vector lenght,
area size ..... )

>
> Let A be (1, 2)
> Let B be (4, 7)
> Let C be (3, 5)
> Let D be (5, 10)
>
> A is smallest; D is largest; how do B and C relate?

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