查詢由降

Question

一組的前兩個元素我有一個表，看起來像這樣：

FruitID | FruitDate | FruitType 
    23 | 10/20/14 | 3 
    32 | 10/12/14 | 3 
    39 | 09/23/14 | 3 

有許多FruitTypes，我想提取包含最後兩個水果對象模型的列表，例如{FruitID : 23, Date: 10/20}, {FruitID : 32, Date: 10/12}

這是我有：

var Output = (from f in MyDC.Fruits 
       where ... some condition 
       orderby f.FruitDate descending 
       group f by f.FruitType in FruitGroups 
       select.... new FruitModel() 
       { 
        FruitID = ... 
        FruitDate = ... 
        FruitType = ... 

       }).ToList(); 

我無法利用最新2.我怎樣才能找回過去的2的列表每個FruitType？

謝謝。

Answer 1

var Output = (from f in MyDC.Fruits 
       where ... some condition 
       orderby f.FruitDate descending 
       group f by f.FruitType in FruitGroups 
       select.... new FruitModel() 
       { 
        FruitID = ... 
        FruitDate = ... 
        FruitType = ... 

       }).Take(2).ToList(); 

後續編輯

新增失蹤from條款;這是查詢：

var Output = (from f in MyDC.Fruits 
       where ... some condition 
       orderby f.FruitDate descending 
       group f by f.FruitType in FruitGroups 
       from t in FruitGroups 
       select new FruitModel() 
       { 
        FruitID = t.FruitID, 
        FruitDate = t.FruitDate 
        FruitType = t.FruitType 

       }).Take(2).ToList(); 

Answer 2

試試這個： -

var query = from fruit in fruitsData 
         group fruit by fruit.FruitType into g 
         select new 
         { 
          FruitType = g.Key, 
          Fruits = g.OrderByDescending(x => x.FruitDate).Take(2) 
         }; 

工作Fiddle。