獲取第二條LINQ中不存在的所有記錄

Question

我想選擇第二條LINQ輸出中不存在FeeZoneID的所有記錄。

我知道它可以很容易地使用NOT IN（....）在SQL中完成，但我在LINQ中做到了嗎？

from d in FeeZones 
where d.FeeZoneID !(from b in FeeZoneSchemes 
    where b.FeeSchemeID == 1 
    join c in FeeZones on b.FeeZoneID equals c.FeeZoneID 
    select c) 
select d 

在我的C＃類，這是我過得怎麼樣：

public IList<FeeZone> _LQ_GetAllAvaliableFeeZoneForGivenFeeSchemeID(int FeeSchemeID) 
    { 
     using(var db = new QualificationContext()) 
     { 
      var query = (from d in db.FeeZone 
         where (!(from b in db.FeeZoneScheme 
           where b.FeeSchemeID == FeeSchemeID 
           join c in db.FeeZone on b.FeeZoneID equals c.FeeZoneID 
           select c).Contains(d.FeeZoneID)) 
         select d).ToList(); 



      return query.ToList(); 
     } 

    } 

這是錯誤： 非常感謝

Answer 1

請嘗試如下所示。

from d in FeeZones 
where (!(from b in FeeZoneSchemes where b.FeeSchemeID == 1 
    join c in FeeZones on b.FeeZoneID equals c.FeeZoneID 
    select c.FeeZoneID).Contains(d.FeeZoneID)) 
select d 

Answer 2

試試這個代碼：

var query = from d in FreeZones 
      let unwantedZonesIds = FeeZoneSchemes.Where(b => b.FreeSchemeID == 1) 
               .Select(b => b.FreeZoneID) 
      where !unwantedZonesIds.Contains(d.FreeZoneID) 
      select d; 

Answer 3

使用Any而不是Contains

var query = (from d in db.FeeZone 
        where (!((from b in db.FeeZoneScheme 
          where b.FeeSchemeID == FeeSchemeID 
          join c in db.FeeZone on b.FeeZoneID equals c.FeeZoneID 
          select c).Any(x => x.FeeZoneID ==d.FeeZoneID)) 
        select d).ToList(); 

Answer 4

您可以使用下面的查詢。

 IList<FeeZones> lst = new List<FeeZones>() { new FeeZones() { FeeZoneID = 1 }, new FeeZones() { FeeZoneID =2 } }; 
     IList<FeeZoneSchemes> lstnew = new List<FeeZoneSchemes>(){new FeeZoneSchemes(){FeeSchemeID=1,FeeZoneID=1}}; 


     var res = (from d in lst 
        where !(
         from c in lstnew 
         join f in lst on c.FeeZoneID equals f.FeeZoneID 
         where c.FeeSchemeID == 1 && c.FeeZoneID == f.FeeZoneID 
         select f.FeeZoneID 
        ).Contains(d.FeeZoneID) 
        select d).ToList(); 

或者您可以使用Sql方式存在查詢如下。

var res = (from d in lst 
        where !(
         from c in lstnew 
         where c.FeeSchemeID == 1 && c.FeeZoneID == d.FeeZoneID 
         select c 
        ).Any() 
        select d).ToList();