c# - LINQ:使用INNER JOIN，组和SUM

我正在尝试使用LINQ执行以下SQL，而我最近得到的是进行交叉联接和求和计算。我知道必须有更好的编写方法，所以我正在向堆栈团队寻求帮助。

SELECT T1.Column1, T1.Column2, SUM(T3.Column1) AS Amount
FROM T1
     INNER JOIN T2
        ON T1.T1ID = T2.T1ID
     INNER JOIN T3
        ON T2.T3ID = T3.T3ID
GROUP BY T1.Column1, T1.Column2

我一直在尝试下面的LINQ代码

var qTotal = from T2 in context.T2
             from T3 in context.T3
             where T3.T3ID == T3.T3ID
             group T3 by T2.T1ID into gT2T3
                  from T1 in context.T1
                  where gT2T3.Key.Equals(T1.T1ID)
                  select new { T1.Column1,T1.Column2,Amount = gT2T3.Sum(t => t.Column1)};

我知道必须有一种更好的编写方法，我只是不知道如何，任何帮助都将非常有用!

最佳答案

试试这个:

var total = from T1 in context.T1
            join T2 in context.T2 on T1.T2ID equals T2.T2ID
            join T3 in context.T3 on T2.T3ID equals T3.T3ID
            group T3 by new { T1.Column1, T1.Column2 } into g
            select new {
                Column1 = T1.Column1,
                Column2 = T2.Column2,
                Amount = g.Sum(t3 => t3.Column1)
            };

关于c# - LINQ:使用INNER JOIN，组和SUM，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/530925/