Re: age() function documentation
От | Peter Eisentraut |
---|---|
Тема | Re: age() function documentation |
Дата | |
Msg-id | Pine.LNX.4.30.0104121928450.1148-100000@peter.localdomain обсуждение исходный текст |
Ответ на | Re: age() function documentation (Thomas Lockhart <lockhart@alumni.caltech.edu>) |
Список | pgsql-hackers |
Thomas Lockhart writes: > Typical date/time arithmetic resolves to an absolute time or interval. > In those cases, *qualitative* quantities such as years and months are > resolved to a specific absolute interval at the time of calculation. > > The age() functions *preserve* the qualitative fields year and month. So > you see the difference in results: > > lockhart=# select age('today', '1957-06-13'); > ------------------------- > 43 years 9 mons 28 days > > lockhart=# select timestamp 'today' - timestamp '1957-06-13'; > ------------ > 16008 days Perhaps age() could be documented along the lines of: Calculates the difference between the arguments and expresses the resulting interval in terms of years, months and possibly smaller units. Ordinary timestamp subtraction is different from age() because it expresses its result only in days and smaller units. Plus a contrasting example, such as the above. -- Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/
В списке pgsql-hackers по дате отправления: