Comments on: Date time paradox http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/ Just another blogs.planetingres.org weblog Thu, 28 Aug 2008 02:02:54 +0000 http://wordpress.org/?v=2.5.1 By: seanb http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-96 seanb Tue, 30 Oct 2007 13:55:15 +0000 http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-96 "I have a date x. and I wish to know the date 10 month befor this x i.e. e.d. if it is 1st nov 2007 then 10 months before would be 1st feb 2007." Surely you would just use date arithmetic? The date you would get 10 months before 1-Nov is 1-Jan. select date('1-nov-07') - '10 months' ==> '1-jan-07' select date('29-dec-07') - '10 months' ==> '28-feb-07' select date('29-dec-08') - '10 months' ==> '29-feb-08' “I have a date x. and I wish to know the date 10 month befor this x i.e. e.d. if it is 1st nov 2007 then 10 months before would be 1st feb 2007.”

Surely you would just use date arithmetic? The date you would get 10 months before 1-Nov is 1-Jan.

select date(’1-nov-07′) - ‘10 months’ ==> ‘1-jan-07′
select date(’29-dec-07′) - ‘10 months’ ==> ‘28-feb-07′
select date(’29-dec-08′) - ‘10 months’ ==> ‘29-feb-08′

]]> By: notnull http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-16 notnull Fri, 21 Sep 2007 07:00:10 +0000 http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-16 From the description it is the number of days between the two dates that are required for the calculation. When using intervals in calculations Ingres assumes the following:Converts a date interval into a floating-point constant expressed in the unit of measurement specified by unit. The interval function assumes that there are 30.436875 days per month and 365.2425 days per year when using the mos, qtrs, and yrs specifications. Using a month interval for calculations subtracts the number of months from the month component of the date leaving the day to be the same unless the day of the month doesn't exist. Trying this with ANSI dates and intervals provides the same behaviour. I've discussed this with John and we think that we're limited by Ingres date/time behaviour but we'll think about it some more. From the description it is the number of days between the two dates that are required for the calculation. When using intervals in calculations Ingres assumes the following:Converts a date interval into a floating-point constant expressed in the unit of measurement specified by unit. The interval function assumes that there are 30.436875 days per month and 365.2425 days per year when using the mos, qtrs, and yrs specifications.

Using a month interval for calculations subtracts the number of months from the month component of the date leaving the day to be the same unless the day of the month doesn’t exist.

Trying this with ANSI dates and intervals provides the same behaviour.

I’ve discussed this with John and we think that we’re limited by Ingres date/time behaviour but we’ll think about it some more.

]]> By: Mrs Raghavan http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-15 Mrs Raghavan Tue, 11 Sep 2007 14:53:59 +0000 http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-15 Hi, I happen to discuss with John Smedly regarding a date concept. I will post it here too. It goes like this: I have a date x. and I wish to know the date 10 month befor this x i.e. e.d. if it is 1st nov 2007 then 10 months before would be 1st feb 2007. This is calculations are needed for some calculations. here various options are when Feb with 28 days or 29 days comes in between or a the calender year changes etc. I do not know how to cater to this without much diffuculty. Till now we are havong a number of if's and else's in the .osq Looking forward to hearing from you thanks Hi,
I happen to discuss with John Smedly regarding a date concept. I will post it here too. It goes like this: I have a date x. and I wish to know the date 10 month befor this x i.e. e.d. if it is 1st nov 2007 then 10 months before would be 1st feb 2007. This is calculations are needed for some calculations. here various options are when Feb with 28 days or 29 days comes in between or a the calender year changes etc. I do not know how to cater to this without much diffuculty. Till now we are havong a number of if’s and else’s in the .osq

Looking forward to hearing from you

thanks

]]> By: Ingres Technology Blog » Blog Archive » ANSI Date Type in latest Ingres Release http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-14 Ingres Technology Blog » Blog Archive » ANSI Date Type in latest Ingres Release Sat, 08 Sep 2007 18:35:40 +0000 http://blogs.planetingres.org/notnull/2007/08/02/date-time-paradox/#comment-14 [...] can definitely search our docs to get all the info you need, but I also found this nice hands on blog entry. Ingres Database Popularity: unranked [?]Share [...] [...] can definitely search our docs to get all the info you need, but I also found this nice hands on blog entry. Ingres Database Popularity: unranked [?]Share [...]

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