Hello!
In database I have two tables:

Students (idStudent, name, surname, dateOfBirth, schoolFee, numberOfRates)
Student(idStudent, rateNumber, amount, dateOfPay)

In crystal report I want to display all students, and they sum of payment of schoolfee but only if dateOfPay is within last month.

name surname dateOfBirth schoolFee @SumOfStudentAmounts

It is easy to display all students information, but I don't know how to create formula that will calculate what sum of amount did student payed?

How to create that formula (@SumOfStudentAmounts)?


Thanks!

Josip