selecting max string

[Borisham]

Hello guys,

This is my data and output needed example.

I would like to select for each student_id the max book_id and then, if there is for that book_id 2 records with the same book_id – I would like to select first the one with a timestamp that existed, if it doesn’t exist – take the null one. So the output should show only one book_id for each student_id.

I hope now the output makes more sense to you.

Thanks

[atcodedog05]

Hi @Borisham 

Here is how you can do it.

Workflow:

Hope this helps : )