Linq to Entities Group By＆Sum

Question

我有下面的Linq查詢返回的數據，但我需要聚合的列在期間和總計計數列組。

我該如何去做這件事？

LINQ

from t In tblTimes 
    join h In tblEngineeringDashboard_CADMachinesCounts on t.ID Equals h.TimeID 
        Order By t.Period 
        Group By t.Period, h.Count Into Group 
        select Period, Count 

DATA

Period     CountΞΞ 
01/01/2010 00:00:00  0 
01/01/2010 00:00:00  1 
01/01/2010 00:00:00  2 
01/01/2010 00:00:00  3 
01/01/2010 00:00:00  5 
01/01/2010 00:00:00  6 
01/01/2010 00:00:00  7 
01/01/2010 00:00:00  9 
01/01/2010 00:00:00  11 
01/01/2010 00:00:00  12 
01/01/2010 00:00:00  14 
01/01/2010 00:00:00  15 
01/01/2010 00:00:00  17 
01/01/2010 00:00:00  21 
01/01/2010 00:00:00  22 
01/01/2010 00:00:00  30 
01/01/2010 00:00:00  31 
01/01/2010 00:00:00  34 
01/02/2010 00:00:00  0 
01/02/2010 00:00:00  1 
01/02/2010 00:00:00  2 
01/02/2010 00:00:00  3 
01/02/2010 00:00:00  5 
01/02/2010 00:00:00  6 
01/02/2010 00:00:00  7 
01/02/2010 00:00:00  9 
01/02/2010 00:00:00  12 
01/02/2010 00:00:00  14 
01/02/2010 00:00:00  15 
01/02/2010 00:00:00  17 
01/02/2010 00:00:00  21 
01/02/2010 00:00:00  23 
01/02/2010 00:00:00  30 
01/02/2010 00:00:00  34 

等

Answer 1

假設你已經檢索到與數據庫的記錄到一個枚舉變量命名爲 'PeriodRecords' 你可以使用下面的LINQ語句得到單個時期和每個時期的總數。

var countsPerPeriod = 
     from row in PeriodRecords  
     group row by row.Period into g 
     select new {Period = g.Key, TotalPeriodCount = g.Group.Sum(row => row.Count)}; 

然後，您可以在您的新的「countsPerPeriod」迭代變量如下：

foreach(var periodCount in countsPerPeriod) { 
    var period = periodCount.Period; 
    var count = periodCount.TotalPeriodCount; 
}