使用「NOT IN」進行LINQ to SQL查詢

Question

可以使用LINQ to SQL查詢使用NOT IN？

如SELECT的au_lname，狀態從作者的WHERE狀態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 }; 

或

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

Answer 2

這裏有一個例子：

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); 

Answer 3

您可以使用Contains：

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

Answer 4

是的！

下面是一個例子，從代碼中，我們已經寫了：

      List<long> badUserIDs = new List { 10039309, 38300590, 500170561 }; 
      BTDataContext dc = new BTDataContext(); 
      var items = from u in dc.Users 
         where !badUserIDs.Contains(u.FbUserID) 
         select u; 

生成的SQL結果是：

{SELECT [t0].[UserID], [t0].[FbUserID], [t0].[FbNetworkID], [t0].[Name], FROM [dbo].[Users] AS [t0] WHERE NOT ([t0].[FbUserID] IN (@p0, @p1, @p2)) }