Linq to SQL中SUM GROUP BY SQL语句的等效写法

Question

我很难想象如何将这个简单的 SQL 语句翻译成 (c#) linq to SQL：

SELECT  table1.vat, SUM(table1.QTY * table2.FLG01 + table1.QTY * table2.FLG04) 
FROM table1
inner join table2 on table2.key= table1.key
where  '2010-02-01' <= table1.trndate   and  table1.trndate <= '2010-02-28'
Group by table1.vat

任何帮助都是受欢迎的

- Savvas Sopiadis

Answer 1

我还在学习LINQ，但这似乎有效

var result = from t1 in table1
             from t2 in table2
             where t1.key == t2.key && DateTime.Parse("2010-02-01") <= t1.trndate && t1.trndate <= DateTime.Parse("2010-02-28")
             group new {t1,t2} by t1.vat into g
             select new { vat = g.Key, sum = g.Sum(p => p.t1.QTY*p.t2.FLG01 + p.t1.QTY*p.t2.FLG04)};

我希望LINQ to SQL也能良好地进行翻译，因为我只在对象上尝试过。

- Jonas Elfström

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是的，它确实奏效了！我想我永远也不会习惯这种Yoda语言。再次非常感谢。 - Savvas Sopiadis

Answer 2

所以在Jonas的帮助下，上述查询变成了这样（使用内连接）：

var result = from t1 in table1
             join t2 in table2 on t1.key equals t2.key
             where  DateTime.Parse("2010-02-01") <= t1.trndate && t1.trndate <= DateTime.Parse("2010-02-28")
             group new {t1,t2} by t1.vat into g
             select new { vat = g.Key, sum = g.Sum(p => p.t1.QTY*p.t2.FLG01 + p.t1.QTY*p.t2.FLG04)};

- Savvas Sopiadis