How to avoid error “aggregate functions are not allowed in WHERE”

Question

This sql code throws an

aggregate functions are not allowed in WHERE

SELECT o.ID ,  count(p.CAT)
FROM Orders o
INNER JO         


        

Answer 1

Use HAVING clause instead of WHERE

Try this:

SELECT o.ID, COUNT(p.CAT) cnt
FROM Orders o
INNER JOIN Products p ON o.P_ID = p.P_ID 
GROUP BY o.ID HAVING cnt > 3