MySQL Inner join and sum two columns

Question

I have the following tables

TABLE: appointments

ID | PRICE | PAID
48 |  100  | 180

TABLE: appointments_product

Answer 1

select b.Appointment_Id, a.price, a.PAID, a.id, sum(b.total) AS TotalProd FROM appointments_products AS b inner join appointments as a On Appointment_Id = a.Id group by Appointment_Id, a.Price , a.PAID , a.id HAVING a.PAID != (a.Price + sum(b.Total))