Linq To EF

l简单查询：
var result = from c in Entities.Customer select c;

l条件查询：

  普通linq写法： var result = from c in Entities.Customer where c.Gender ==‘w’ select c;

  Lambda表达式写法：   var result = from c in Entities.Customer.Where<Customer>(c =>c.Gender==‘w’);

         排序分页写法： IQueryable<Customers> cust10 = (from c in customers

l                                         orderby c.CustomerID

l                                         select c).Skip(0).Take(10);

 

l左外连接：可以的连接有Join 和 GroupJoin 方法。GroupJoin组联接等效于左外部联接，它返回第一个（左侧）数据源的每个元素（即使其他数据源中没有关联元素）。

l var query = from d in edm.Order_Details

l                   join order in edm.Orders

l                   on d.OrderID equals order.OrderID

l                   select new

l                    {

l                        OrderId = order.OrderID,

l                        ProductId = d.ProductID,

l                        UnitPrice = d.UnitPrice