Question

I have the below Linq query that is returning the data but I need to aggregate the columns to group on the Period and Sum the Count columns.

How do I go about doing this?

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

etc

Answer 1

Assuming you have retrieved your records from the database into an enumerable variable named ‘PeriodRecords’ you could use the following Linq statement to get the individual periods and the sum of count per period.

 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)};

You can then iterate over your new “countsPerPeriod” variable as follows;

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