Number of trimesters between two dates

Question

Number of trimesters between two dates

Rem70Rem

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Points: 6166
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August 10, 2010 at 11:42 am

#236476

Hi,
I need to find the number of trimester between 2 dates.
For example if I want to find the number of relative quarter between two dates I use "select datediff(qq, '2010-03-30', '2010-04-01')". This will return 1 since they are not in the same quarter.
For trimester, there is not parameter to use datediff, si I need to build a function to do it. To find a trimester I am using this "select ((MONTH('2010-09-01')-1) / 4) + 1", but I need to find the number of trimester between two dates.
I was thinking to use something like this "select cast (datediff(dd, '2010-08-30', '2010-09-01')/121.66666 as int)" where 121.66666 is the average days in a trimester. This doesn't works since when there is a switch of trimester the number of days is smaller then 121.66666, we need almost 3 months difference to have a valid result.
Any hint?
Thanks

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Michael Valentine Jones SSC Guru Points: 64818 More actions · Answer 1

I think you need to post a usable definition of exactly what a trimester is before someone can write code to give you a trimester.

Rem70Rem SSCertifiable Points: 6166 More actions · Answer 2

Here my trimesters:

A trimester is period of three months

Jan to Apr = Trimester #1

May to Aug= Trimester #2

Sep to Dec = Trimester #3

I also need to get the number of trimesters between 2 dates even if they are not in the same year. For example, for the number of quarter between 2 dares not in the same year...select datediff(qq, getdate(), '2009-04-01')=-5

Thanks for your help

Michael Valentine Jones SSC Guru Points: 64818 More actions · Answer 3

Rem-487422 (8/10/2010)
Here my trimesters:
A trimester is period of three months
Jan to Apr = Trimester #1
May to Aug= Trimester #2
Sep to Dec = Trimester #3
Thanks for your help

Your trimesters have four months, not three months.

select

Trimester = ((datepart(month,a.MyDate)-1)/4)+1 ,

a.*

from

( -- Test Data

select MyDate = dateadd(month, 0,getdate())union all

select MyDate = dateadd(month, 1,getdate())union all

select MyDate = dateadd(month, 2,getdate())union all

select MyDate = dateadd(month, 3,getdate())union all

select MyDate = dateadd(month, 4,getdate())union all

select MyDate = dateadd(month, 5,getdate())union all

select MyDate = dateadd(month, 6,getdate())union all

select MyDate = dateadd(month, 7,getdate())union all

select MyDate = dateadd(month, 8,getdate())union all

select MyDate = dateadd(month, 9,getdate())union all

select MyDate = dateadd(month,10,getdate())union all

select MyDate = dateadd(month,11,getdate())union all

select MyDate = dateadd(month,12,getdate())

) a

Results:

Trimester MyDate

----------- -----------------------

2 2010-08-10 14:40:03.560

3 2010-09-10 14:40:03.560

3 2010-10-10 14:40:03.560

3 2010-11-10 14:40:03.560

3 2010-12-10 14:40:03.560

1 2011-01-10 14:40:03.560

1 2011-02-10 14:40:03.560

1 2011-03-10 14:40:03.560

1 2011-04-10 14:40:03.560

2 2011-05-10 14:40:03.560

2 2011-06-10 14:40:03.560

2 2011-07-10 14:40:03.560

2 2011-08-10 14:40:03.560

Rem70Rem SSCertifiable Points: 6166 More actions · Answer 4

Thanks Michael, but I need to find the number of trimesters between 2 dates, even if they are no tin the same year.

Ex:

2010-05-10 and 2010-07-01 will be 0

2010-04-30 and 2010-05-01 will be 1

2010-05-30 and 2009-12-30 will be 2

2010-05-30 and 2008-12-30 will be 6

many thanks for your help.

drew.allen SSC Guru Points: 76996 More actions · Answer 5

I'm comparing the difference in months between the zero date and each date, dividing that by four (using integer division) and then subtracting the two values.

DateDiff(Month, 0, FirstDateField)/4 - DateDiff(Month, 0, SecondDateField)/4

Drew

J. Drew Allen
Business Intelligence Analyst
Philadelphia, PA

Rem70Rem SSCertifiable Points: 6166 More actions · Answer 6

Thx all.

I did write function but the one of Drew is way more elegant.

Rem

jcrawf02 SSC-Insane Points: 24198 More actions · Answer 7

Are you using 'trimester' in a medical sense? If so, you should be aware that the first trimester is two weeks longer than the next two, since it's calculated off the LMP date.

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Rem70Rem SSCertifiable Points: 6166 More actions · Answer 8

I am using the trimester for financial purposes not medical. Thanks for bringing this point...