LINQ to SQL查询使用"NOT IN"

Question

LINQ to SQL查询可以使用NOT IN吗？

例如,SELECT au_lname,state FROM authors WHERE state NOT IN('CA','IN','MD')

Answer 1

    List<string> states = new List<string> { "CA", "IN", "MD" };
    var q = from a in authors
            where !states.Contains(a.state)
            select new { a.au_lname, a.state };

要么

   var q = authors.Where( a => !states.Contains( a.state ) )
                  .Select( a => new { a.au_lname, a.state } );

Answer 2

你可以用Contains来做:

       var states = new[]  {"CA", "IN", "MD"};
       var query = db.Authors.Where(x => !states.Contains(x.state));

Answer 3

这是一个例子:

NorthwindDataContext dc = new NorthwindDataContext();
dc.Log = Console.Out;
var query =
    from c in dc.Customers
    where !(from o in dc.Orders
            select o.CustomerID)
           .Contains(c.CustomerID)
    select c;
foreach (var c in query) Console.WriteLine( c );