Working with SAS format dates

[viollete]

Hello,

I have all my info about dates in SAS format and I want from each date subtract nine months.

Is it possible to do?

[LinusH]

intnx()

[RichardinOz]

Linus' reply is a bit terse.  The intnx function will provide an answer, provided you supply the right question.  Do you want 9 calendar months exactly (ie to the same day - if possible - 9 months previously), or do you just need the month and the first day will do; or maybe push all dates back by the same amount (0.75 year = 274 days)?

Taking these options in reverse order:

Prev_date = date - 274 ;

Prev_date = intnx("MONTH", date, -9) ;

Prev_date = intnx("MONTH", date, -9, "SAME") ;

INTNX is documented here

SAS(R) 9.2 Language Reference: Dictionary, Fourth Edition

BTW, if your dates are datetime intervals you need to use "DTMONTH" instead of "MONTH" ; and for the 274 day calculations use

Prev_date = intnx("DTDAY", date, -274, "SAME") ;

Richard