How can I sum the fields?
I have two tables that I want to match. One is about reservations and other is about services. One code of reservations can have a lot of codes of services. So, I want to know, how can I sum the fields of related tables? and how do I sum the fields that only that belong to a single code. For example: Reservation Code 1, Services Code 2,4 and 5, so when I go to the register 1 of reservation I want to see the codes of the services and also their names and prices but I want a sum just of the codes 2,4,5 that belong to the code 1 of reservation.
Thanks for the help