Re: How to sum and group by?

[Peter Brawley]

Master: Customer Information
Id = BigInt
Name = varchar

Detail: Orders Information
Id = BigInt
CustomerId = BigInt (related to Master table)
InvoiceNumber = Int
Year = int
Price = decimal

Is this what you mean?

select c.id, d.year, sum(d.price) as total
from customers c
join details d on c.id=d.customerid
group by c.id, d.year;

BTW your id, customerid and year columns are overkill. You don't expect to have 9 quintillion customers or sales, probably smallint unsigned would do, and you'll never get past a year that fits in a smallint unsigned.