Re: comparison operators

On 2014-06-17 19:22:07 -0400, Tom Lane wrote:
> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> > I went to have a look at documenting the jsonb comparison operators, and
> > found that the docs on comparison operators contain this:
>
> > Comparison operators are available for all relevant data types.
>
> > They neglect to specify further, however. This doesn't seem very
> > satisfactory. How is a user to know which are relevant? I know they are
> > not available for xml and json, but are for jsonb. Just talking about
> > "all relevant types" seems rather hand-wavy.
>
> Well, there are 38 default btree opclasses in the standard system ATM.
> Are we worried enough about this to list them all explicitly? Given the
> lack of complaints to date, I'm not.
>
> However, if we try to fudge it by saying something like "available for
> all data types for which there is a natural linear order", I'm not
> sure that that's 100% true; and it's certainly not complete, since
> for instance jsonb's ordering is rather artificial, and the area-based
> orderings of the built-in geometric types are even more so.

It's not true for e.g. xid (which is rather annoying btw).

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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