Problem to extract right information in array

[user40]

I have some duplicated stays in my dataset that i need to extract the last number of this. In the same data I also have some id that have overlap dates, that i only need to take out the longest stay in hospital. In addition, I have also some stay in hospitals that one stay follow the other one. That i asked you what should I do? 

Se the following dataset that i have under here: Data that i have

I want that i extract last observation for P00009779 that is sekv =5, max daydiff for P0000066881 that is daydiff =19 and sum all stays for P000209192 that is complicated for me. Is there a nice tip to do this for each problem and merge data after?

[PeterClemmensen]

Please post what you want the desired result to look like. Makes it much easier to provide a usable code answer.

[user40]

I cannot add code since the code on a server