On Sat, 18 Feb 2006, Tom Lane wrote: > "Milen A. Radev" <[EMAIL PROTECTED]> writes: > > Milorad Poluga ????????????: > >>> SELECT '10 years 1 mons 1 days'::interval - '9 years 10 mons 15 > >>> days'::interval > >>> ?column? > >>> --------------- > >>> 3 mons -14 days > >>> > >>> Why not '2 mons 16 days' ? > > > Please read the last paragraph in section 8.5.1.4 of the manual > > (http://www.postgresql.org/docs/8.1/static/datatype-datetime.html#AEN4775) > > . It mentions the functions named "justify_days" and "justify_hours" > > that could do what you need. > > justify_days doesn't currently do anything with this result --- it > thinks its charter is only to reduce day components that are >= 30 days. > However, I think a good case could be made that it should normalize > negative days too; that is, the invariant on its result should be > 0 <= days < 30, not merely days < 30.
What about cases like interval '1 month -99 days', should that turn into interval '-3 mons +21 days' or '-2 mons -9 days'? ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
