Question

通常在t-sql中，如果我使用：

SELECT *
FROM Orders
INNER JOIN Customers
ON Orders.CustomerID=Customers.CustomerID;

它返回所有表的所有列，如何在linq中实现？

尝试：

var query = from siparis in db.Siparis
            join kazan in db.Kazan on siparis.ID equals kazan.Siparis_ID into Joined
            select Joined;

但它只返回我的对象，而不是一切。

Answer 1

您需要返回两个对象或每个对象的选择。这在您的问题的评论中指定。但我只是想一个例子会有所帮助。

var query = from siparis in db.Siparis
            join kazan in db.Kazan on siparis.ID equals kazan.Siparis_ID 
            select new { 
                         siparis, 
                         kazan
                       };

或

var query = from siparis in db.Siparis
            join kazan in db.Kazan on siparis.ID equals kazan.Siparis_ID 
            select new { 
                         SiparisID = siparis.ID, 
                         KazanID = kazan.ID,
                         SiparisColumnX = sipariz.X,
                         KazanColumnX = kazan.X
                       };

Answer 2

这是等效的

var query = from siparis in db.Siparis
               join kazan in db.Kazan on siparis.ID equals kazan.Siparis_ID
               select siparis;

为了获得结果，最后添加.ToList，如

var query = (from siparis in db.Siparis
               join kazan in db.Kazan on siparis.ID equals kazan.Siparis_ID
               select siparis).ToList();

LINQ等效于连接查询;

2 个答案: