Re: Custom type where not all elements are comparable

Markus Bertheau wrote:
> Is it possible to define or implement a type in PostgreSQL not all
> values of which are comparable to each other? In particular I'm
> thinking of a duration type similar to the XML Schema duration
> type[1]. For example P2D (2 days) is less than P4D (4 days), but P1M
> (1 month) and P30D (30 days) are not comparable.

Smells like the interval type.