I have TableA listing purchase orders. I have TableB listing Inbound Shipments. Each shipment record references a purchase order. What I want is a LinqToSql clause that will return those purchase order records from TableA that are not yet on a shipment. In SQL this would be simple:
SELECT * FROM Orders WHERE OrderID NOT IN (SELECT OrderID FROM Shipments).
try this http://introducinglinq.com/blogs/marcorusso/archive/2008/01/14/the-not-in-clause-in-linq-to-sql.aspx