Question

尝试将简单的SQL查询编写为LINQ。

这是SQL：

SELECT p.id, p.customer, SUM(pd.total_price)
FROM purchases p JOIN purchases_details pd ON p.id = pd.purchase_id
GROUP BY pd.purchase_id

到目前为止我最好的LINQ：

var purchases_with_details = from p in db.Purchases
                             join pd in db.Purchases_details on p.Id equals pd.purchase_id
                             group pd by pd.purchase_id into pdg
                             select new { ??? };

问题是我只能在pdg.*中写select new { }。

我想写一些类似{ p.id, p.customer, pdg.Sum(o => o.total_price) }

的内容

任何人都知道怎么做？

Answer 1

尝试：

     var purchases_with_details = from pd in db.Purchases_details
                                         group pd by pd.purchase_id into pdg
                                         //join *after* group
                                         join p in db.Purchases on pdg.Key equals p.Id
                                         select new
                                         {
                                             Id = p.Id,
                                             Cust =p.customer,
                                             TotalPrice = pdg.Sum(y => y.total_price)
                                         };

Answer 2

你可以尝试这个

var purchases_with_details = from p in db.Purchases
                             join pd in db.Purchases_details on p.Id equals pd.purchase_id
                             group pd by pd.purchase_id into pdg
                             select new { 
                                 PurchaseID=pdg.Key.purchase_id,
                                 TOTAL=pdg.Sum(x=>x.total_price)
                             };

SQL到LINQ，分组和总和

2 个答案: