MYSQL calculating an average on a count

Question

I have a simple query that I want an average on. This is what it looks like now, and I want to know the average of my count per Opname_OpnameID.

SELECT Opname_O         


        

Answer 1

You can use count(distinct) and not use a subquery:

SELECT count(*) / count(distinct Opname_OpnameID)
FROM behandeling