topic Re: Date Differences Calculation in SAS Procedures

Date Differences Calculation

gnt1986 — Mon, 04 Nov 2013 21:52:56 GMT

data myfile;

set file1;

tdy=&pbd_date;

ckdt=CK007_dt;

age=tdy-ckdt;

format age date9.;

run;

In our database &pbd_date is a numeric that can be converted to a date format. ckdt is also a numeric

When I run the code, it initially produces numerics and a difference (ie 19663 - 19604 = 59)

If I format the age variable to a date9 I get wierd dates in the past (ie 19663 - 19604 = 29FEB1960)

If I format tdy ckdt age to date9 I get something like (01NOV2013-03SEP2013=29FEB1960)

I want the difference between 11/1/13 and 9/1/13 to be expressed in the actual date that is between the tdy and ck_dt.

Re: Date Differences Calculation

ballardw — Mon, 04 Nov 2013 22:26:02 GMT

When you subtract a date from another date you get the number of days between the values. Since SAS uses a base of 01Jan1960 for 'date' 0 then 59 days later is 29 Feb 1960.

If you need to get a count of specific intervals, such as months or weeks you want the INTCK function.

Re: Date Differences Calculation

art297 — Mon, 04 Nov 2013 22:34:18 GMT

Not sure why you are calling your result "age" but, from what you described, does the following come close?:

%let pbd_date=19663;

data file1;

informat ck007_dt date9.;

input ck007_dt;

cards;

03sep2013

;

data myfile;

set file1;

tdy=&pbd_date;

ckdt=CK007_dt;

age=tdy+((tdy-ckdt)/2);

format age date9.;

run;

Re: Date Differences Calculation

MumSquared — Mon, 04 Nov 2013 22:45:10 GMT

I would use intck ...

data dates;
format d_now dob date9.;
d_now=today();
dob="1jan1970"d;
age_years=intck('years',dob,d_now);
run;

proc print data=dates; run;

This gives:

Obs d_now dob age_years

1 05NOV2013 01JAN1970 43