Question

I have two tables with a one to many relation.

One Order has many Products.

I want to take a list of Orders with the free Product in each (one per order).

I’ve tried something like this:

this.ObjectContext.ORDERS.Include("PRODUCTS").Where(e=>e.PRODUCTS.price == 0).OrderBy(e => e.Order);

But this is not working.

Is there any other approach??

Thanks in advance.

Answer 1

if PRODUCTS is a collection, you can use the Any() extension method to find out if any product is free (alternatively, the All() method to find out if all products are free):

this.ObjectContext.ORDERS
                  .Include("PRODUCTS")
                  .Where(o => o.PRODUCTS.Any(p => p.price == 0))
                  .OrderBy(e => e.Order);

Based on your clarification of the desired output (all orders with optional free product), you can use this query:

this.ObjectContext.ORDERS
                  .Include("PRODUCTS")
                  .Select(o => new {
                      Order = o, 
                      FreeProduct = o.PRODUCTS.FirstOrDefault(p => p.price == 0)
                  });

It will return a sequence of an anomymous type containing the order, and the free product (or null if no free product exists).