On Postgres did you try TIMESTAMPADD or did you try timestamp + interval? I ask because if we fix this, we are going to have to change the behavior of timestamp + interval.
Also please change the JIRA case subject to something more descriptive. For the SQL standard, search for "ISO/IEC 9075-2” and you can find some committee drafts. Not the final standard, but good enough for our purposes. Julian > On Feb 16, 2017, at 12:37 AM, hongbin ma <mahong...@apache.org> wrote: > > Hi Julian > > Thanks for you reply. > > I have confirmed on postgresql, it behaves exactly as mysql. > > For ansi SQL 92 I could find http://www.contrib.andrew.cmu.edu/~shadow/sql/ > sql1992.txt, however for SQL 2011 I can't find a counterpart source. Can > you please kindly show me a link? just to make sure we're at same page. > > > > On Thu, Feb 16, 2017 at 2:29 PM, Julian Hyde <jh...@apache.org> wrote: > >> Can you please log a JIRA case for this? >> >> It seems that we implement TIMESTAMPADD(unit, n, t) as “t + interval n >> unit”. E.g. timestampadd(MONTH, 1, DATE ‘2016-05-31’) translates to DATE >> ‘2016-05-31’ + INTERVAL ‘1’ MONTH. Similarly TIMESTAMPDIFF. >> >> So, can you please investigate whether we got interval addition and >> subtraction wrong too. I think you should check the SQL standard >> (preferably SQL-2011 or SQL-2014 draft) and also test on PostgreSQL. >> >> Julian >> >>> On Feb 15, 2017, at 10:16 PM, hongbin ma <mahong...@apache.org> wrote: >>> >>> hi experts >>> >>> in calcite, >>> >>> select timestampadd(MONTH,1,cast('2016-05-31' as timestamp)) will >>> return 2016-07-01 00:00:00, and select >>> timestampadd(MONTH,-1,cast('2016-03-31' as timestamp)) will >>> return 2016-03-01 00:00:00 >>> >>> however in mysql, the last day of the next/previous month is always >>> returned: >>> >>> *mysql> select timestampadd(MONTH,1,'2016-05-31') ;* >>> *+------------------------------------+* >>> *| timestampadd(MONTH,1,'2016-05-31') |* >>> *+------------------------------------+* >>> *| 2016-06-30 |* >>> *+------------------------------------+* >>> *1 row in set (0.00 sec)* >>> >>> *mysql> select timestampadd(MONTH,-1,'2016-03-31') ;* >>> *+-------------------------------------+* >>> *| timestampadd(MONTH,-1,'2016-03-31') |* >>> *+-------------------------------------+* >>> *| 2016-02-29 |* >>> *+-------------------------------------+* >>> *1 row in set (0.00 sec)* >>> >>> *mysql> * >>> >>> I checked ANSI SQL 92, seems there's no definition on this. >>> Is this an issue we should concern? Looks like mysql's approach is more >>> straigthtforward. >>> >>> >>> -- >>> Regards, >>> >>> *Bin Mahone | 马洪宾* >> >> > > > -- > Regards, > > *Bin Mahone | 马洪宾*
