Re: '1 year' = '360 days' ????
От | Bruno Wolff III |
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Тема | Re: '1 year' = '360 days' ???? |
Дата | |
Msg-id | 20041024045120.GA16743@wolff.to обсуждение исходный текст |
Ответ на | Re: '1 year' = '360 days' ???? (Bruno Wolff III <bruno@wolff.to>) |
Ответы |
Re: '1 year' = '360 days' ????
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Список | pgsql-general |
On Sat, Oct 23, 2004 at 23:15:57 -0500, Bruno Wolff III <bruno@wolff.to> wrote: > by comparing say m1 and m2. This will work as long as f(m,s1) = f(m,s2) > implies s1 = s2. It will probably be desirable to use a subset of these > mappings where f(m,s) = g(m) + h(s). In fact the current system uses > this with g(m) = 30*24*60*60*m and h(s) = s (but without the tiebreak > that compares m values). Because of the way intervals work, I think > you want to use an ordering generated like that you want to use > something of the form f(m,s) = C1*m + C2*s. I also think that treating > a month as 30 days and having round numbers is better than using > something like 1/12 a solar year in seconds. So I think the best plan > is to do things as they are now, except for adding a tie breaker just > using months or seconds for when both intervals give the same number of > seconds when treating months as 30 days, but have a different number of > months. Some more comments on this. I was thinking about it a bit more and using 1/12 of the number of seconds in a solar year doesn't seem that bad for comparisons. That way 366 days > 1 year > 365 days. However, if you go that route, I think you would also want to change EXTRACT so that when you extract the EPOCH you use the same function as for comparison. One value I found for a solar year is 365 days, 5 hours, 48 minutes, 45.51 seconds.
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