Re: INTERVAL type: SQL92 implementation

Thomas Lockhart <lockhart(at)fourpalms(dot)org> wrote:
> We have a copy of an SQL99 draft which seems to be reasonably complete.
> afaik we haven't come across an actual released version. Let me know if
> you want me to forward it; perhaps it is on the ftp or web site?

ftp://ftp.postgresql.org/pub/doc/sql/sql1998.tar.gz

Mostly the same files are at
http://gatekeeper.research.compaq.com/pub/standards/sql/
(or ftp).

I didn't know until recently that the ANSI standard was available in PDF
form for an almost reasonable price ($18/part) compared to the outrageous
ISO price ($98 to $275 per part).

See http://webstore.ansi.org/ansidocstore/find.asp?find_spec=sql

[...]
> Not sure what you mean here. The existing type does keep years/months
> stored separately from the days/hours/minutes/seconds (a total of two
> internal fields) but SQL99 asks that these be kept completely away from
> each other from what you've said. Does it define any arithmetic between
> the two kinds of intervals?

No. Days/hours/minutes/seconds are exact quantities whereas years and
months are not, so they don't mix.