_SubtractMonths ( vDate ; vLessMonths )

Subtract x number of months from a given date

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Makah Encarnacao
Soliant Consulting
http://www.soliantconsulting.com/

Sample input:

_SubtractMonths ( "1/26/2015" , 9 )

Sample output:

4/26/2014

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

/*@ Created by Makah Encarnacao at Soliant Consulting
   @ mencarnacao@soliantconsulting.com*/

Let(
[
vMonth = Month( vDate); 
vDay = Day( vDate);
vYear = Year( vDate)
];

Case(
Sign( vMonth - vLessMonths ) = -1; 
Date( vMonth - vLessMonths + 12; vDay; vYear -1); 
Date( vMonth - vLessMonths; vDay; vYear)
)
)

This function will subtract months from a given date, for example 5/15/2014 - 3 months = 2/15/2014. It is subtracting from the month value, and does not modify the day value (although FileMaker may automatically modify the day value if the resulting date is not valid). If you would like to add months instead of subtract months, you can tweak the custom function or see my function _AddMonths or enter a negative value for the 2nd parameter.

Comments

		Tim Anderson, Tim Anderson Group Sep 2, 2015
As I have suggested for you _AddMonths cf, just subtract the number of months, FileMaker will sort out the years

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

_SubtractMonths ( vDate ; vLessMonths )

Comments

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