04-15-2014 03:18 PM
If I had a dataset that contained a Diabetes_Date and a Hypertension_date like the following:
ID Diabetes_date Hypertension_date
111 4/5/05 7/10/06
222 3/4/14 9/6/10
I need a new variable date that would list the date at which they had both Diabetes and Hypertension. So for the above example it would be 7/10/06 for 111 and the 222 ID would be 3/4/14. I know I could do a few if statements to accomplish this, but wondering if there are other easy methods.
Thanks so much!
04-16-2014 06:11 AM
No, I do not think max() propagates nulls unless all the parameters are null. In fact I use max(value, 0) to set missing values to zero. You need the N() function as well to count the number of non null values.
If n(Diabetes_date, hypertension_date) = 2
then combined Date = max(diabetes_date,hypertension_date) ;
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