Tom Lane wrote:
If I read SQL 200N's spec correctly
select interval '-1 1:00:00';
should mean "-1 days -1 hours",
yet 8.3 sees it as "-1 days +1 hours".
I think we are kind of stuck on this one. If we change it, then how
would one represent -1 days +1 hours? The spec's format is only sane
I'm not proposing this, but I could imagine making
"-1 -1:00:00" and/or "-1 +1:00:00" mean -1 days +1 hours.
I think if it weren't for backward compatibility issues I'd even
support such an idea - since now we're oh-so-very-close to accepting
to-spec literals. Unfortunately I fear old users might assume the
opposite meaning.
Scary to touch that one, but since a standard's a standard, I think
eventually we should get there.
The SQL spec's date/time handling is, and always has been, broken enough
that I feel no great compulsion to follow every last detail. Especially
details that make it impossible to support our extensions...
In this case we're so very close to meeting the spec, though. And
it's ashame where we accept the to-spec syntax ("-1 1:00:00") but
return a different answer.
And since it's not quite impossible to support our extensions (force
putting the sign on the h:m:s part for mixed sign cases) I feels nice
to me to try.
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