If I have the following tables/entities:

Invoice
- InvoiceId (PK)
- InvoiceAmount

InvoicePayment
- InvoicePaymentId (PK)
- InvoiceId (FK)
- PaymentAmount

How can I construct a Linq to Entity query that selects invoices with an outstanding amount - bearing in mind that the existence of a payment does not indicate that the invoice does not have an outstanding amount (i.e. partial payment are possible).

• c#-4.0
• linq-to-entities

I would go for something along the lines of this

from i in invoices
where i.Payments.Sum(p=>p.PaymentAmount) < i.InvoiceAmount
select i;