MySQL Select only one row from each patient diagnosed according the first date

Question

EDIT

I cannot group by only with patient_id, I will get an error of sql_mode=only_full_group_by...

I

Answer 1

Just keep the group by clause t1.patient_id, t5.date_of_assessment.

So I read this doc if you don't require order by order by assisment date remove it, or keep the same in group by also.