Обсуждение: BUG #6178: date_trunc : interval units "week" not supported contradicts documentation
BUG #6178: date_trunc : interval units "week" not supported contradicts documentation
От
"Noah Hamerslough"
Дата:
The following bug has been logged online: Bug reference: 6178 Logged by: Noah Hamerslough Email address: noah@pcc.com PostgreSQL version: 8.4 Operating system: Windows Vista Description: date_trunc : interval units "week" not supported contradicts documentation Details: http://www.postgresql.org/docs/8.4/static/functions-datetime.html#FUNCTIONS- DATETIME-TRUNC The documentation for date_trunc('field', source) lists 'week' in the as a valid value for 'field' However, if the source is an interval, 'week' is not supported. select date_trunc('week', '1 month 15 days'::interval); ERROR: interval units "week" not supported SQL state: 0A000 Either 'week' should be supported or the documentation should be updated to reflect that it is not.
Re: BUG #6178: date_trunc : interval units "week" not supported contradicts documentation
От
Bruce Momjian
Дата:
On Thu, Aug 25, 2011 at 07:05:34PM +0000, Noah Hamerslough wrote: > > The following bug has been logged online: > > Bug reference: 6178 > Logged by: Noah Hamerslough > Email address: noah@pcc.com > PostgreSQL version: 8.4 > Operating system: Windows Vista > Description: date_trunc : interval units "week" not supported > contradicts documentation > Details: > > http://www.postgresql.org/docs/8.4/static/functions-datetime.html#FUNCTIONS- > DATETIME-TRUNC > > The documentation for date_trunc('field', source) lists 'week' in the as a > valid value for 'field' However, if the source is an interval, 'week' is not > supported. > > select date_trunc('week', '1 month 15 days'::interval); > > ERROR: interval units "week" not supported > SQL state: 0A000 > > Either 'week' should be supported or the documentation should be updated to > reflect that it is not. Turns out the reason we don't support this is because there are usually a fractional number of weeks in a month, so there is no good way to do this for intervals. I have applied the attached patch to PG 9.3 which will explain why this is not supported. I saw this as better than a documentation mention. -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +