一个最好的例子

表名:TBL_Emp和TBL_Dep

var result = from emp in TBL_Emp join dep in TBL_Dep on emp.id=dep.id
select new
{
 emp.Name;
 emp.Address
 dep.Department_Name
}


foreach(char item in result)
 { // to do}

var Data= (from dealer in Dealer join dealercontact in DealerContact on dealer.ID equals dealercontact.DealerID
select new{
dealer.Id,
dealercontact.ContactName

}).ToList();

因为我更喜欢表达式链语法，下面是你如何做到这一点:

var dealerContracts = DealerContact.Join(Dealer, 
                                 contact => contact.DealerId,
                                 dealer => dealer.DealerId,
                                 (contact, dealer) => contact);

OperationDataContext odDataContext = new OperationDataContext();    
        var studentInfo = from student in odDataContext.STUDENTs
                          join course in odDataContext.COURSEs
                          on student.course_id equals course.course_id
                          select new { student.student_name, student.student_city, course.course_name, course.course_desc };

学生和课程表在哪里有主键和外键的关系

使用Linq Join操作符:

var q =  from d in Dealer
         join dc in DealerConact on d.DealerID equals dc.DealerID
         select dc;

基本上LINQ连接操作符对SQL没有好处。例如，下面的查询

var r = from dealer in db.Dealers
   from contact in db.DealerContact
   where dealer.DealerID == contact.DealerID
   select dealerContact;

将导致内部连接在SQL

join对IEnumerable<>有用，因为它更有效:

from contact in db.DealerContact  

条款将对每个经销商重新执行 但对于IQueryable<>则不是这样。另外，连接也不太灵活。