Re: Support for RANGE ... PRECEDING windows in OVER

On 06/21/2013 05:32 PM, Hitoshi Harada wrote:

> I also later found that we are missing not only notion of '+' or '-',
> but also notion of 'zero value' in our catalog.  Per spec, RANGE BETWEEN
> needs to detect ERROR if the offset value is negative, but it is not
> always easy if you think about interval, numeric types as opposed to
> int64 used in ROWS BETWEEN.

Zero can be tested for with `val = (@ val)` ie `val = abs(val)`. That
should make sense for any type in which the concept of zero makes sense.

Thanks for the warning on that issue.

-- Craig Ringer                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services