Question

I need to perform a LINQ query for both a time period from a database table (Period) and a list of invoices from a table (Invoice) that fall within the period’s start and end dates. There is no key reference between the two tables, how can I do the Invoice subquery?

I am trying to do something similar to the following:

var query = (from p in db.DataContext.Periods              // Subquery i in db.DataContext.Invoices              let InvoiceAmount = i.Where(t => t.InvoiceDate >= p.StartDate && t.InvoiceDate <= p.EndDate)              select new PeriodView              (                 p.Name,                 p.StartDate,                 p.EndDate,                 InvoiceAmount.Count()               )); 

Answer 1

var periodViewList =      (from p in db.DataContext.Periods     select new PeriodView(       p.Name,       p.StartDate,       p.EndDate,       db.DataContext.Invoices.Where(i => i.InvoiceDate >= p.StartDate && i.InvoiceDate <= p.EndDate).Count()     )).ToList(); 

I’m assuming that the PeriodView constructor looks something like this

public PeriodView (string name, DateTime startDate, DateTime endDate, int invoiceCount) { ... }