Re: comparison operators

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.

regards, tom lane