Re: check contraint allows illegal value? - Mailing list pgsql-bugs

missive@frontiernet.net (Lee Harr) writes:
> Is this a bug?

> create table foo( c char(2)
>     check (c in ('09', '10', '11', '12', 'n/a'))
> );

I don't think so; at least, I don't think there's any way in the general
case for the system to realize that some part of a check condition can
never succeed or never fail.  (See "halting problem".)

            regards, tom lane