linq groupby() 和 Sum()

Question

这可能很微不足道，但我无法让它工作（linq 级别的新手）。

我想对同一天的客户的行进行分组和求和（日期显示在 epoc/unixtime 中）。

目前它只是将最大值显示为 21（从 Kbytes 转换为 Gbytes），而不是我想要看到的 ±26。

如何添加 GroupBy 和 Sum 子句以添加每天的千字节？

public class Images
{
    public string ClientName { get; set; }
    public string ImageID { get; set; }
    public int PolicyType { get; set; }
    public int ScheduleType { get; set; }
    public Int64 BackupTime { get; set; }
    public Int64 KBytes { get; set; }
}

和

public static List<Images> images = new List<Images>();

和

    public void calc()
    {

        foreach (var client in clients)
        {
            totalmax = 0;
            totalavg = 0;
            foreach (var ptype in ptypes)
            {

                var windowsquery = images
                    .Where(s => s.PolicyType == Convert.ToInt16(ptype) && s.ScheduleType == 0 && s.ClientName == client)
                    .Select(s => s.KBytes);

                double typemax = windowsquery.DefaultIfEmpty().Max()/1048576;
                totalmax = Math.Round(totalmax + typemax);
                double typeavg = windowsquery.DefaultIfEmpty().Average()/1048576;
                totalavg = Math.Round(totalavg + typeavg);

            }
            Console.WriteLine("Client = {0}, Max = {1}, Ave = {2}", client,totalmax, totalavg);
            Console.ReadKey();
        }
    }

输出（从输出中省略其他客户端）

Client = Client2，Max = 21，Ave = 14

更新：实现了这个

var summary = (from image in images
                           where image.ScheduleType == 0
                           group image by new
                           {
                               image.ClientName,
                               image.PolicyType,
                               image.ScheduleType,
                               BackupDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0)
                                                                       .AddSeconds(image.BackupTime)
                                                                       .ToString("yyyy-MM-dd")
                           } into imageGroup
                           select new
                           {
                               ClientName = imageGroup.Key.ClientName,
                               PolicyType = imageGroup.Key.PolicyType,
                               BakupDateTime = imageGroup.Key.BackupDateTime,
                               SumGBytes = imageGroup.Sum(s => s.KBytes) / 1048576.0,
                               AvgGBytes = imageGroup.Average(s => s.KBytes) / 1048576.0,

                           }
                                    ).ToList();

但总和不正确，平均值工作正常。

Answer 1

检查这个：

var summary = (from image in images
               group image by new { image.ClientName, 
                                    image.PolicyType,
                                    BackupDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0)
                                                .AddSeconds(image.BackupTime)
                                                .ToString("MM/dd/yyyy", CultureInfo.InvariantCulture)
                                  } into imageGroup
               select new { ClientName = imageGroup.Key.ClientName, 
                            PolicyType = imageGroup.Key.PolicyType,
                            BakupDateTime = imageGroup.Key.BackupDateTime,
                            SumGBytes = imageGroup.Sum(s => s.KBytes) / 1048576.0,
                            AvgGBytes = imageGroup.Average(s => s.KBytes) / 1048576.0,
                            MaxGBytes = imageGroup.Max(s => s.KBytes) / 1048576.0,
                            Records = imageGroup.Count()
                          }
              ).ToList();

您可以使用以下查询列出所有已转换 BackupTime 的记录：

var listWithDateTime = (from image in images
                        orderby image.ClientName ascending, 
                                image.PolicyType ascending, 
                                image.BackupTime ascending
                        select new { 
                                 ClientName = image.ClientName,
                                 PolicyType = image.PolicyType,
                                 GBytes = image.KBytes / 1048576.0,
                                 UnixTimestamp = image.BackupTime,
                                 NormalDate = new DateTime(1970, 1, 1, 0, 0, 0, 0)
                                            .AddSeconds(image.BackupTime)
                                            .ToString("MM/dd/yyyy", CultureInfo.InvariantCulture) 
                               }
                       ).ToList();

Answer 2

好像是重复发帖，Stack Overflow 中已经有答案了...

var windowsquery = images
                .Where(s => s.PolicyType == Convert.ToInt16(ptype) && s.ScheduleType == 0 && s.ClientName == client).GroupBy(s => YourDateField)
                .Select(s => s.Sum(i => i.KBytes));

或

 var windowsquery = images
                        .Where(s => s.PolicyType == Convert.ToInt16(ptype) && s.ScheduleType == 0 && s.ClientName == client).GroupBy(s => YourDateField)
                        .Select(g=>new { sum = g.Sum(k=>k.KBytes), field = g.Key });

Answer 3

你已经试过这个了吗？

 var windowsquery = images
                    .Where(s => s.PolicyType == Convert.ToInt16(ptype) 
                     && s.ScheduleType == 0 && s.ClientName == client)
                    .GroupBy(s => s.date)
                    .Select(s => s.Sum(y=>y.KBytes));

在您添加的图片中，日期似乎不正确还是特殊格式？