Design and Architecture

var anonCustWithOrderCt = from c in db.Customers
                          where c.LastName = "Smith"
                          select new
                          {
                              c.CustomerID,
                              c.LastName,
                              c.FirstName,
                              OrdersInLastSixMonths = c.Orders.Count(o => o.OrderDate > DateTime.Now.AddMonths(-6))
                          }

SELECT [t0].[CustomerID], [t0].LastName, [t0].FirstName, (
    SELECT COUNT(*)
    FROM [Orders] AS [t1]
    WHERE ([t1].[OrderDate] > @p0) AND ([t1].[CustomerID] = [t0].[CustomerID])
    ) AS [OrdersInLastSixMonths]
FROM [Customers] AS [t0]
WHERE [t0].LastName = 'Smith'
-- @p0: Input DateTime (Size = 0; Prec = 0; Scale = 0)

var query = from o in MyObjects select o;

// Apply dynamic criteria
if (minID > Int32.MinValue)
{
    query = query.Where(o => o.ID >= minID);
}

if (maxID > Int32.MaxValue)
{
    query = query.Where(o => o.ID <= maxID);
}

if (name != null && IsEqual)
{
    query = query.Where(o => o.Name == name);
}
else if (name != null && ContainedWithin)
{
    query = query.Where(o => o.Name.Contains(name));
}

// Apply dynamic order by
switch (orderField)
{
    case "Name": query = query.OrderBy(o => o.Name); break;
    case "ID": query = query.OrderBy(o => o.ID); break;
    default: query = query.OrderBy(o => o.OrderIndex); break;
}

// Our query is now set up, lets iterate it to retrieve and process data
foreach (var result in query)
{
    Console.WriteLine("ID: " + result.ID + ", Name: " + result.Name);
}