Re: absolute value fro timestamps
Bruce Momjian wrote:
Why would you want an abolute value of a negative interval?
Because I'm trying to match pairs of records that satisfy certain criteria,
one of which is that both records have a timestamp that *may* be slightly
offset between them, so I substract the two and the result must be no
greater than the allowed offset. I don't know which record has the greater
timestamp, so I don't know the sign of the substraction in advance.
This works:
test=> select -(interval '-1');
?column?
----------
01:00:00
(1 row)so I suppose you could create a function or CASE statement to get the
absolute value.
In the meantime I implemented it the following way:
\set maxoffset 4
select
...
where
abs(extract(epoch from age(m1.ts, m2.ts))) < :maxoffset
...
Which I think is more compact. Anyway, it would be nice to be able to write
directly
abs(age(m1.ts, m2.ts))
IMHO.
thanks
cl.
Import Notes
Reference msg id not found: 200309032113.h83LDjc28519@candle.pha.pa.us
"Claudio Lapidus" <clapidus@hotmail.com> writes:
Bruce Momjian wrote:
Why would you want an abolute value of a negative interval?
Because I'm trying to match pairs of records that satisfy certain criteria,
Given that we have a unary-minus operator for intervals, I see no
conceptual objection to having an absolute-value operator (and \do shows
that interval is the only standard datatype that has the former but not
the latter).
However, given that it doesn't seem to be a really widely useful
operator, I think this is the kind of itch that you'll have to scratch
yourself. Send us a patch and it'll get into the next release ...
regards, tom lane