Confusion about the range types

Dino Maric <dinom@hey.com> writes:

When I insert range like this:
INSERT INTO public.tests
VALUES (int4range(7,8,'[]'))
After when querying table my return value for this column is not [7,8]
but it is [7,9).
I found this behaviour confusing, because I want to insert 7-8 ranges
(including upper value) and then present that range to a user.

This is the effect of canonicalization, as explained here:

https://www.postgresql.org/docs/current/rangetypes.html#RANGETYPES-DISCRETE

If you don't like it you can make a range type with a different
canonicalization function, or no such function, but that might
have odd effects on the behavior of range comparison operators.

regards, tom lane

Thanks Tom, I understand.

But still it does feel a bit strange that value I'm storing is different
when presenting.
For example I want to use range in healthcare app and value user stores
it must be the same when presenting.
So in that case it is [7-8] and [7-9) are not the same thing :)

On January 7, 2023, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Dino Maric <dinom@hey.com> writes:

When I insert range like this:
INSERT INTO public.tests
VALUES (int4range(7,8,'[]'))
After when querying table my return value for this column is not

[7,8]

but it is [7,9).
I found this behaviour confusing, because I want to insert 7-8

ranges

(including upper value) and then present that range to a user.

This is the effect of canonicalization, as explained here:

https://www.postgresql.org/docs/current/rangetypes.html#RANGETYPES-
DISCRETE

If you don't like it you can make a range type with a different
canonicalization function, or no such function, but that might
have odd effects on the behavior of range comparison operators.

 regards, tom lane

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