Re: BUG #4974: Equivalent of "= ANY" and "BETWEEN" not observed by planner. - Mailing list pgsql-bugs

"Ian Turner" <ian.turner@deshaw.com> writes:
> The following queries are equivalent, because there are no integers between
> 5 and 6 and because the BETWEEN operator contemplates a closed range.
> SELECT * FROM example WHERE pk IN (5,6);
> SELECT * FROM example WHERE pk BETWEEN 5 AND 6;

The planner intentionally does not do very many inferences that are as
datatype-dependent as this one would be.  It doesn't fit into the system
design.  For the most part the possible gain is not large anyway.

            regards, tom lane