Re: Oddity with literal intervals

Tom Lane wrote:

> Mike Mascari <mascarm@mascari.com> writes:
>>Here's something odd I stumbled upon:
>
>>[estore@lexus] select now() - '1 day';
>>ERROR:  invalid input syntax for type timestamp with time zone: "1 day"
>
> What's odd about it?  The preferred interpretation is timestamptz minus
> another timestamptz (yielding an interval).  If you want timestamptz
> minus interval (yielding timestamptz), you have to do something to cue
> the system that the literal should be taken as an interval.
>
> The "+" cases work because there is no timestamp plus timestamp operator.

Okay. That's why I posted it to -general and not -bugs, because I
suspected there was some reason behind it. I guess it seemed odd
because it has been on rare occasion that I have encountered types
where there exists a '-' operator without a corresponding '+'
operator. And, coincidentally having a '+' operator available for
timestampz + interval just added to my confusion. But the above
makes perfect sense.

Thanks!

Mike Mascari