LinqToEntities查詢沒有加入的記錄

Question

我有TableA列出採購訂單。我有TableB列出入庫貨件。每個貨件記錄都參考採購訂單。我想要的是一個LinqToSql子句，它將返回TableA尚未發貨的那些採購訂單記錄。在SQL這將是簡單的：

SELECT * FROM Orders WHERE OrderID NOT IN (SELECT OrderID FROM Shipments). 

Answer 1

試試這個http://introducinglinq.com/blogs/marcorusso/archive/2008/01/14/the-not-in-clause-in-linq-to-sql.aspx

Answer 2

假設DbSets叫個PurchaseOrder和出貨量再像這樣應該足夠了：

db.PurchaseOrders.Where(
    p => !db.Shipments.Select(s => s.OrderID).Contains(p.OrderID) 
)