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
If you want the average count, presumably over the entire table, then just do exactly that:
SELECT AVG(cnt) AS total_avg
FROM (
SELECT COUNT(*) AS cnt FROM behandeling GROUP BY Opname_OpnameID
) t;
You can use count(distinct)
and not use a subquery:
SELECT count(*) / count(distinct Opname_OpnameID)
FROM behandeling