You should post your data as a data step. Instructions here: https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-dat... will show how to turn an existing SAS data set into data step code that can be pasted into a forum code box using the {i} icon or attached as text to show exactly what you have and that we can test code against.
Show the start data and the desired result. I think what you show is a final data set with extra varaibles that aren't needed.
Paste data into a text box using the {i} icon. I don't know what you pasted that data from but I can't paste into an editor in a form I'm
willing to spend the time to write a data step to read.
Is your Xnumber for Patiend 173 supposed to go from 2 to 6? If so what is the rule?
Something along these lines may get you started if I understand that the overlapping visit dats are counted as one visit and the count should be sequential.
proc sort data=have;
by Patient_RK start_date End_date;
run;
data want;
set have;
by Patient_rk;
retain xstart xend xnumber;
format xstart xend ddmmyy10.;
if first.Patient_rk then do;
xstart=start_date;
xend = end_date;
xnumber=1;
end;
else do;
if start_date <= xend then do;
/* continuation of previous visit*/
xend = end_date;
end;
else do;
/* new visit*/
xnumber+1;
xstart=start_date;
xend = end_date;
end;
end;
run;
