Question

我正在尝试创建一个计算所有订单的表，并将它们分组到从sql到linq的表中，以便在带有谷歌图表的条形图中使用。

Table`

Orders  Status
8       Created
3       Delayed
4       Enroute

SQL

SELECT Count (OrderID) as 'Orders', order_status FROM [ORDER]
where order_status ='Created'OR order_status= 'Delayed' OR order_status='Enroute'
group by order_status

控制器

  public ActionResult GetChart()
    {
        var Orders = db.Order.Select(a => new { a.OrderID, a.order_status })
                             .GroupBy(a => a.order_status);

        return Json(Orders, JsonRequestBehavior.AllowGet);
    }

这并没有显示正确的结果，因为linq似乎是错误的。有人可以指出我正确的方向吗？我对此比较陌生。提前谢谢。

Answer 1

这应该有效： -

var result = db.Order.Where(x => x.order_status == "Created"
                             ||  x.order_status == "Delayed"
                             ||  x.order_status == "Enroute")
                     .GroupBy(x => x.order_status)
                     .Select(x => new 
                                  {
                                       order_status = x.Key,
                                       Orders = x.Count()
                                  });

或者，如果您更喜欢查询语法，那么： -

var result = from o in db.Order
             where o.order_status == "Created" || o.order_status == "Delayed" 
                || o.order_status == "Enroute"
             group o by o.order_status
             select new 
                    {
                        orderStatus = x.Key,
                        Counts = x.Count()
                    };

Answer 2

我认为您希望按Status进行分组并计算每个组中的订单总数（我构建了一个简单的控制台程序来演示）。我想数据是：

Orders  Status
8       Created
3       Delayed
4       Enroute
2       Created
1       Delayed

<强> Order.cs

public class Order
{
    public Order(int orderId, string status)
    {
        OrderId = orderId;
        Status = status;
    }

    public int OrderId { get; set; }
    public string Status { get; set; }
}

<强> Program.cs的

class Program
{
    static void Main(string[] args)
    {
        // Data
        var orders = new List<Order>
        {
            new Order(8, "Created"),
            new Order(3, "Delayed"),
            new Order(4, "Enroute"),
            new Order(2, "Created"),
            new Order(1, "Delayed"),
        };

        // Query
        var query = orders
            .GroupBy(x => x.Status)
            .Select(x => new {Status = x.Key, Total = x.Count()});

        // Display
        foreach (var item in query)
        {
            Console.WriteLine(item.Status + ": " + item.Total);
        }
        Console.ReadLine();
    }
}

您需要关注的是query。使用GroupBy后，您将获得一个组列表。对于每个组，Key是要分组的条件（此处为Status）。然后，我们调用Count()来获取该组中元素的总数。

因此，从上面的程序中，输出应为：

Created: 2
Delayed: 2
Enroute: 1

使用来自sql查询的linq计数和分组

2 个答案: