Question

Here is my scenario (Tables):

Orders
======================
Id (int)  
description (varchar)

Products
======================
Id (int)
description (varchar)

OrderProductXREF (cross reference table)
======================
ProductId (int)
OrderId (int)

I think you get an idea. Nothing unusual is here.

When imported to EDMX file OrderProductXREF table is not visible entity. All I see is navigational properties: Products for entity Order and Orders for entity Product.

So, my problem:
I need Linq and/or Lambda statement that will list all Products that don’t have any Orders associated with. Or, list all Products that are never ordered.

SQL would go like this:

SELECT * FROM Products
WHERE Id NOT IN 
   (SELECT ProductId 
    FROM OrderProductXREF)

EDIT:
Uh… sorry forgot one little detail in my question.

Here is the new SQL:

SELECT * FROM Products
WHERE Id NOT IN 
   (SELECT ProductId 
    FROM OrderProductXREF
    WHERE OrderID = 1)

In words, All Products that are NOT ORDERED in order with ID = 1

Thanks

Answer 1

Apologies – misread the question beforehand. I suspect you want:

var query = db.Products.Where(product => !product.Orders.Any());

You should definitely check the generated SQL though. I would expect it to be sensible, but if it’s not, you would probably want to look at other alternatives.

EDIT: To check products not in order ID 1, you could probably use:

var query = db.Products.Except(db.Orders
                                 .Where(order => order.Id == 1)
                                 .Single()
                                 .Products);

Or:

var query = db.Products.Where(product => !product.Orders
                                                 .Where(order => order.Id == 1)
                                                 .Any());