Sql server 如何在LINQ中执行此SQL

早上好，我想知道如何在LINQ中使用（MS）SQL

 SELECT CONVERT(CHAR(10),orderDate,110)  AS OrderDate, 
 SUM(1) AS TotalOrders 
 FROM Orders
 WHERE OrderDate>getdate()-30
 GROUP BY CONVERT(CHAR(10),orderDate,110)
 ORDER BY OrderDate DESC

非常感谢

更新 我结束了使用和编辑下面提供的解决方案的版本，我想我会分享它

 using (DataDataContext dc = new DataDataContext())
        {
            var query = from o in dc.Orders
                        where o.orderDate > DateTime.Now.AddDays(-30)
                        let dt = o.orderDate
                        group o by new DateTime(dt.Year, dt.Month, dt.Day) into g
                        select new OrderCounts
                        {
                            OrderDate = String.Format("{0:d}", g.Key.Date),
                            TotalOrders = g.Count()
                        };

            query.GroupBy(o => o.OrderDate);
            query.OrderBy(o => o.OrderDate);

            return query.ToList();
        }

查询将被删除

var query = from o in res
                        where o.OrderDate > DateTime.Now.AddDays(-30)
                        orderby o.OrderDate descending
                        group o by o.OrderDate into g                       
                        select new
                        {
                            OrderDate = g.Key.Date.ToString("MM/dd/yyyy")
                            ,
                            TotalOrders = g.Sum(i=> 1)
                        };

或者通过Lambda表达式

var query= res
                        .Where(i => i.OrderDate > DateTime.Now.AddDays(-30))
                        .OrderByDescending(o => o.OrderDate)
                        .GroupBy(g => g.OrderDate)
                        .Select(s => new { OrderDate = s.Key.Date.ToString("MM/dd/yyyy"), TotalOrders = s.Sum(i => 1) });

---

g、 Sum（1）似乎不想工作？错误45“System.Linq.IGrouping”不包含“Sum”的定义和最佳扩展方法重载“System.Linq.Enumerable.Sum（System.Collections.Generic.IEnumerable，System.Func）”有一些无效的参数。请注意，所有日期都是按顺序排列的，而不是按顺序分组的，有什么想法吗？Sum（1）不只是进行计数吗？为什么要使用sum（1）当有一个非常好的（可能更适合）选项可用时？我尝试了你的代码，它也带回了过去30天的所有订单，并且没有按日期分组-顺便说一句，我有一个datetime字段。

var query= res
                        .Where(i => i.OrderDate > DateTime.Now.AddDays(-30))
                        .OrderByDescending(o => o.OrderDate)
                        .GroupBy(g => g.OrderDate)
                        .Select(s => new { OrderDate = s.Key.Date.ToString("MM/dd/yyyy"), TotalOrders = s.Sum(i => 1) });