如何編寫此LINQ查詢

Question

嗨，我有一個包含以下字段的數據表

DAT_START
GROUPBY
TXT_LATITTUDE
TXT_LONGITUDE
INT_DIRECTION
INT_CALL_DATA_TYPE
LNG_DURATION

以下是我正在使用的LINQ查詢

var data = (from r in dt.AsEnumerable()
where ((r.Field<DateTime>("DAT_START").TimeOfDay.Hours < 20) && (r.Field<DateTime>("DAT_START").TimeOfDay.Hours >= 4))
group r by new { CID = r["GroupBy"], CLatitude = r["TXT_LATITUDE"], CLongitude = r["TXT_LONGITUDE"],CDirection = r["INT_DIRECTION"], 
CCallType = r["INT_CALL_DATA_TYPE"],CDuration = r["LNG_DURATION"] }
into groupedTable
select new
{
   CellID = groupedTable.Key.CID,
   CallCount = groupedTable.Count(),
   Longitude = groupedTable.Key.CLongitude,
   Latitude = groupedTable.Key.CLatitude,
   Direction = groupedTable.Key.CDirection,
   CallType = groupedTable.Key.CCallType,
   Duration = groupedTable.Key.CDuration
}).OrderByDescending(s => s.CallCount);

它給我這樣的結果

CellID = 4057,CallCount = 84,Longitude = "",Latitude = "",Direction = "Incoming",CallType = "Voice",Duration = 50
CellID = 4057,CallCount = 8,Longitude = "",Latitude = "",Direction = "Outgoing",CallType = "Voice",Duration =97
CellID = 4057,CallCount = 56,Longitude = "",Latitude = "",Direction = "Incoming",CallType ="SMS" ,Duration = 0
CellID = 4057,CallCount = 41,Longitude = "",Latitude = "",Direction = "Outgoing",CallType = "SMS",Duration = 0

現在我想要這樣的結果

CellID = 4057, TotalCommCount = 204, TotalDuration = 147, INSMSCount = 56,OutSMSCount = 41, INVoiceCount = 84,OutVoiceCount = 8,InVoiceDuration =50,OutVoiceDuration = 47

我怎樣才能做到這一點。 我被打到這里了。

Answer 1

看來您目前分組過多，這就是為什么要獲得多行的原因。 我懷疑您想要這樣的東西：

from r in dt.AsEnumerable()
where r.Field<DateTime>("DAT_START").TimeOfDay.Hours < 20 && 
      r.Field<DateTime>("DAT_START").TimeOfDay.Hours >= 4
group r r["GroupBy"] into g         
select new
{
    CellID = g.Key,
    TotalCommCount = g.Count(),
    TotalDuration = g.Sum(r => r.Field<long>("LNG_DURATION")),
    InSMSCount = g.Count(r => r.Field<string>("DIRECTION") == "Incoming" &&
                              r.Field<string>("CALL_TYPE") == "SMS"),
    OutSMSCount = g.Count(r => r.Field<string>("DIRECTION") == "Outgoing" &&
                               r.Field<string>("CALL_TYPE") == "SMS"), 
    InVoiceCount = g.Count(r => r.Field<string>("DIRECTION") == "Incoming" &&
                                r.Field<string>("CALL_TYPE") == "Voice"),
    OutVoiceCount = g.Count(r => r.Field<string>("DIRECTION") == "Outgoing" &&
                                 r.Field<string>("CALL_TYPE") == "Voice"),
    InVoiceDuration = g.Where(r => r.Field<string>("DIRECTION") == "Incoming" &&
                                r.Field<string>("CALL_TYPE") == "Voice")
                       .Sum(r => r.Field<long>("DURATION"))
    OutVoiceDuration = g.Where(r => r.Field<string>("DIRECTION") == "Outgoing" &&
                                    r.Field<string>("CALL_TYPE") == "Voice"),
                       .Sum(r => r.Field<long>("DURATION"))
 } into summary
 order by summary.TotalCommCount descending
 select summary;

Answer 2

我建議您在SQL數據庫中創建一個視圖，您可以在其中簡單地聚合所需的內容，然后在Linq查詢中使用該視圖-這樣可以快速執行並且易於編寫。

設計草圖：

由於您對需求的描述並不十分清楚，因此我做了一些假設。 創建一個SQL視圖，例如（只是為了顯示想法，根據您的需要進行更改）：

CREATE VIEW [dbo].[vSumDurations]
AS 
select  c.CellId, j1.SumDuration1 as TotalDuration, 
        j2.SumDuration2 as GroupedDuration, j1.CallCount  
from (select distinct t.CID as CellId from [dbo].[YourTable] t) c
left join (select t1.CID as CellId, sum(LNG_Duration) as SumDuration1, 
            count(*) as CallCount from [dbo].[YourTable] t1 
            Group By t1.CID) j1 
on c.CellId=j1.CellId           
left join (select t2.CID as CellId, sum(LNG_Duration) as SumDuration2 
            from [dbo].[YourTable] t2 
            Group by t2.CID, t2.Direction, t2.CallType) j2 
on c.CellId=j2.CellId

（您知道您可以通過使用實體圖頁面的上下文菜單中的“從數據庫更新模型”，然后在對話框的“表/視圖”部分中標記視圖vSumDurations，輕松地將此視圖添加到* .EDMX中。彈出。）

准備好之后，您的Linq查詢非常簡單，因為視圖中的所有操作均已完成。 因此，代碼如下所示：

var dc = this; // in LinqPad you can set your data context
var data = (from d in dc.vSumDurations select d).OrderByDescending(s => s.CallCount);
data.Dump();

注意：該示例是針對LinqPad制作的-您的實際代碼中將需要其他數據上下文。 Linqpad不需要dc ，但是出於方便的原因聲明它會更容易，因為您必須在實際代碼中提供它。