轉換加入和集團通過從SQL到LINQ

Question

我是新的LINQ，我需要幫助轉換這個SQL代碼：要LINQ

SELECT UserId_FK,COUNT(OrderId),SUM(Quantity) 
    FROM Orders o 
    JOIN OrderDetails od 
    ON(o.OrderId = od.OrderId_FK) 
    GROUP BY UserId_FK; 

Answer 1

沒有看到你的架構文件，我將採取猜測這裏：

var userDetail = 
    context.Orders 
     .GroupBy(i => i.UserId_Fk) 
     .Select(i => new { 
         UserId_Fk = i.Key, 
         OrderCount = i.Count(), 
         ProductQuantity = i.Sum(j => context.OrderDetails.Where(k=> k.OrderId_Fk == j.OrderId).Sum(k=> k.Quantity)) 
         });