Re: Patch for SQL-Standard Interval output and decoupling DateStyle from IntervalStyle

Ah. And one final question regarding functionality.

It seems to me that the last remaining place where we input
a SQL-2008 standard literal and do something different from
what the standard suggests is with the string:
'-1 2:03:04'
The standard seems to say that the "-" affects both the
days and hour/min/sec part; while PostgreSQL historically,
and the patch as I first submitted it only apply the negative
sign to the days part.

IMHO when the IntervalStyle GUC is set to "sql_standard",
it'd be better if the parsing of this literal matched the
standard. We already have the precedent where DateStyle
is used to interpret otherwise ambiguous output.

If the IntervalStyle is set to anything other than sql_standard
we'll keep parsing them the old way; so I think backwards
compatibility issues would be minimized. And those
using the sql_standard mode are likely to be standards
fanatics anyway, and would probably appreciate following the
standard rather than the backward compatible mode.

Thoughts?
I have a version of each alternative working here,
and I'd be happy to submit the final patch either way.