CODEWITHSUNDEEP
c#entity-framework
szpic
szpic

Reputation: 4496

How to add SUM aggregate function into Entity Framework query

I have a query:

var resultb = unitOfWork.deviceInstanceRepository.Get()
            .Select(s => new
            {
                DeviceId = s.DeviceId,
                Name = s.Device.Name,
                Manufacturer = s.Device.Manufacturer1.Name,
                Quantity = s.Quantity
            })
            .GroupBy(w => new
            {
                w.DeviceId,
                w.Name,
                w.Manufacturer,
                w.Quantity
            }).ToList();

I want to change this line: Quantity= s.Quantity

into

Quantity=Sum(s=>s.Quantity)

I found this Click but still have some problems with implementing this. There is no Sum method in Intellisense.

Ok when I change places of Select and GroupBy :

var resultb = unitOfWork.deviceInstanceRepository.Get()
            .GroupBy(w => new
            {
                w.DeviceId,
                w.Device.Name,
                w.Device.Manufacturer,
                w.Quantity
            })
            .Select(s => new
            {
                DeviceId = s.DeviceId,
                Name = s.Device.Name,
                Manufacturer = s.Device.Manufacturer1.Name,
                Quantity = s.Sum(s=>s.Quantity)
            })

I can use Sum but then lines like : s.DeviceId throws error that Anonymous type does not contain definition of deviceId. Same error for s.Device.Name and s>device.Manufacuter1.Name

Upvotes: 1

Views: 8910

Answers (1)

Gert Arnold
Gert Arnold

Reputation: 109079

You must do the grouping without the Quantity property, because that is the property you want to aggregate in the grouping:

unitOfWork.deviceInstanceRepository.Get()
          .GroupBy(w => new
          {
              DeviceId = w.DeviceId,
              Device = w.Device.Name,
              Manufacturer = w.Device.Manufacturer,
          })
          .Select(s => new
          {
              DeviceId = s.Key.DeviceId,
              Name = s.Key.Device,
              Manufacturer = s.Key.Manufacturer.Name,
              Quantity = s.Sum(x => x.Quantity)
          })

Upvotes: 5

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