LINQ查询对应的SQL

Question

下面是我的SQL语句，我不能转换到LINQ

select o.CustId,c.CustName,Count(o.CustId) as Total_Orders from Customer c 
inner join Orders o on c.CustId = o.CustId group by o.CustId,c.CustName 

Answer 1

以下是LINQ查询（db是的EntityFramework DBContext）。

var query = from c in db.Customers 
      join o in db.Orders on c.CustId equals o.CustId into g 
      groupby new { CustID = c.CustId, CustName=c.CustName } into gs 
      select new { CustID = gs.Key.CustId, CustName=gs.Key.CustName, Count= gs.Count() } into gs 

Answer 2

请尝试：

var query = from c in Customer 
      join o in Orders 
      on c.CustId 
      equals o.CustId 
      group x by new {o.CustId, c.CustName} 
      into g 
       select new 
       { 
        g.Key.CustId, 
        g.Key.CustName, 
        Total_Orders = g.Count() 
       }; 

Answer 3

什么这样的事情？

var query = db.Customers.Select(c => new 
       { 
        CustId = c.CustId, 
        CustName = c.CustName, 
        Total_Orders = db.Orders.Where(o => o.CustId == c.CustId).Count() 
       } 
      ); 

Answer 4

var query = from c in context.Customers 
      select new 
      { 
       c.CustId, 
       c.CustName, 
       Orders = c.Orders.Count(), 
      };