Hi!   I was wondering what I am doing wrong. I want to make a starting point of my follow-up (date_start1) and I have different dates of measurement (date1, date2, date3 etc.) and I want to pick the date which is nearest to the date of questionnaire completion (dataq) as my date_start1. Most of the time date_start1 is date1. But sometimes date2-4 are closer to the date of questionnaire completion.     When I do this: DATA want; SET have; date_start1=date1; IF abs((date1-dataq)/365.25) GT abs((date2-dataq)/365.25) THEN date_start1=date2; ELSE IF abs((date1-dataq)/365.25) OR abs((date2-dataq)/365.25) GT abs((date3-dataq)/365.25) THEN date_start1=date3; ELSE IF abs((date1-dataq)/365.25) OR abs((date2-dataq)/365.25) OR abs((date3-dataq)/365.25) GT abs((date4-dataq)/365.25) THEN date_start1=date4; FORMAT date_start1 DATE9.; RUN;   I don't get good results. SAS doesn't pick this:  date_start1=date1;    It seems SAS only picks: IF abs((date1-dataq)/365.25) GT abs((date2-dataq)/365.25) THEN date_start1=date2;   What should I do? Thanks in advance!  ... View more

When I want to merge 6 datasets to one dataset like this: *Merge datasets*; DATA m.combined; MERGE m.dataset1 m.dataset2 m.dataset3 m.dataset4 m.dataset5 m.dataset6; BY personnumber; RUN; Why do I get in my output table 3 times the same measurements for my personnumber like this:  Personnumber  Gender Heigth Weight 1   1  167  56 1   1  167  56 1   1  167  56 2   1  188  78 2   1  188  78 2   1  188  78 3   2  190  102 3   2  190  102 3   2  190  102   I want to merge it like this:  Personnumber  Gender  Heigth Weight 1  1   167  56 2  1   188  78 3  2   190  102   There are no errors, so can someone please help? Thanks! ... View more