subtracting 2 dates

[lmyers2]

Hello

I'm trying to find the number of years between 2 dates. The variables have the following attributes. I'm not sure why the code I have below isn't working.

                              Length  Format    Informat   Label

data want; set have;

length=year(datepart(EVRPRDTTM))-year(datepart(adate));

run;

The date is arranged in columns. There is only 1 row per patient.

                     adate    EVRPRDTTM

Patient 1

Patient 2

Patient 3...

[SASKiwi · Accepted solution]

Looks like ADATE is a date not a datetime variable so try this and switch to the INTCK function for greater accuracy:

data want; set have;

length=intck('YEAR', adate, datepart(EVRPRDTTM), 'C');
run;

[lmyers2]

Thanks - what does the C do in the code?

[SASKiwi]

@lmyers2  - It's explained in the link I included (C = CONTINUOUS). If you still don't follow after reading that then please advise.

[Tom]

The DATEPART() function is for converting datetime values (seconds) into date values (days).  It is essentially doing a MOD() operation with number of seconds in a day.  If you give a date value, like you are doing the result will be zero, which is 01JAN1960, since there are more seconds in a day than there are days since 1960 to now.

1460  data _null_;
1461    today=date();
1462    day = '24:00't ;
1463    put (_all_) (=comma12.);
1464  run;

today=22,361 day=86,400