topic Re: Difference between two dates in SAS Programming

Difference between two dates

GN0001 — Thu, 10 Feb 2022 04:02:48 GMT

Hello team,

I need to find out if DateofService that are within 30 days of the dischargedate.

I appreciate your help.

Regards,

blue & blue

Re: Difference between two dates

Tom — Thu, 10 Feb 2022 04:19:12 GMT

If they both contain DATE values then just test is the absolute value of the difference is less than or equal to 30.

Make sure to protect against missing values and SAS will consider a missing value as less than any actual number.

if -1 < abs(DateofService-dischargedate) <= 30 then .....

Re: Difference between two dates

GN0001 — Thu, 10 Feb 2022 05:18:09 GMT

Hello Tom,

Thanks for your response.
why should I use abs?
if dateofservice is less than discharge date, then that is ok. We want to find out those records when they had a visit within 30 days after their discharge.

if we use abs, then we can’t find out within 30 days after thr discharge date.

can’t we use datedif?

how should I guard against missing values? If discaregedate or dateofservice ne.?

yes both values are dates. I think if the result is positive, then dos has occurred after discharge date. Then, I need to find out if it is between 0 to 30 days.

regards

blue & blue

Re: Difference between two dates

SASKiwi — Thu, 10 Feb 2022 07:05:38 GMT

Just swap your variables then:

if 1 <= (dischargedate - DateofService) <= 30;

Not sure what happens if both happen on the same day. Do you want to count those? If so change the 1 to 0.

Re: Difference between two dates

Kurt_Bremser — Thu, 10 Feb 2022 07:23:44 GMT

All your questions regarding date values are answered here:

Working with Dates in the SAS System

Studying these documents will make most of your date-related posts here unnecessary.

Re: Difference between two dates

GN0001 — Thu, 10 Feb 2022 16:39:50 GMT

Hello,
Why don’t I say if difference is > 0 and <= 30?
And should I find the difference first and then bring if?
Respectfully,
Blueblue

Re: Difference between two dates

Tom — Thu, 10 Feb 2022 17:49:37 GMT

Because you asked for "within 30 days", which would imply plus or minus 30 days.

Re: Difference between two dates

SASKiwi — Thu, 10 Feb 2022 19:25:50 GMT

"Why don’t I say if difference is > 0 and <= 30?"

You'll get the same results as in my logic.

"And should I find the difference first and then bring if?"

Up to you, which ever way is best for you. There is no right or wrong answer here.

Re: Difference between two dates

GN0001 — Fri, 11 Feb 2022 21:44:46 GMT

Hello Kurt,

What you have directed me are links after links. If I want to get that route, I would be lost and each day, I need to start working in a new company. Obviously, reading is essential part of gaining education, I always read and search and then I post my question here.

I clicked on the links then other links came up and then till seven layers deep that I forgot what I wanted.

Anyway, thank you for sending me the direction that I go back and read them after I deliver my projects. I have short deadlines.

Respectfully,

Blue & Blue