Linq Sum based on some columns

Question

I have a query returning some values for a specific CompanyId and a Specific Month/Year.

I want to make a report for the whole year. (So I need to sum up the values from different months, but of the same year and CompanyId)

Here is my query now:

from er in EconomicReports
join com in Companies on er.CompanyId equals com.Id
join cou in Countries on com.CountryId equals cou.Id
where er.Year == 2014
select new 
{
Country = cou.Name,
CompanyId = com.Id,
CorporationId = com.CorporationId,
Year = er.Year,
RegisteredCases = er.NewCasesTotalCount,
RegisteredCasesAmount = er.NewCasesTotalAmount,
ResolvedCases = er.ClosedCasesTotalCount,
ResolvedCasesAmount = er.ClosedCasesCapitalAmount + er.ClosedCasesInterestAmount,
ActiveCases = (er.NewCasesTotalCount ?? 0) - (er.ClosedCasesTotalCount ?? 0),
ActiveCasesAmount = (er.NewCasesTotalAmount ?? 0) - (er.ClosedCasesCapitalAmount ?? 0) -  (er.ClosedCasesInterestAmount ?? 0)
}

Basically, rows 1 and 5 need to be one row, because they are from the same year, same company Id (I have put also Month in the results for you to see that is a different month, but same year)

Answer 1

you need a GroupBy:

var query = (from er in EconomicReports
            join com in Companies on er.CompanyId equals com.Id
            join cou in Countries on com.CountryId equals cou.Id
            where er.Year == 2014
            select new 
            {
                Country = cou.Name,
                CompanyId = com.Id,
                CorporationId = com.CorporationId,
                Year = er.Year,
                RegisteredCases = er.NewCasesTotalCount,
                RegisteredCasesAmount = er.NewCasesTotalAmount,
                ResolvedCases = er.ClosedCasesTotalCount,
                ResolvedCasesAmount = er.ClosedCasesCapitalAmount + er.ClosedCasesInterestAmount,
                ActiveCases = (er.NewCasesTotalCount ?? 0) - (er.ClosedCasesTotalCount ?? 0),
                ActiveCasesAmount = (er.NewCasesTotalAmount ?? 0) - (er.ClosedCasesCapitalAmount ?? 0) -  (er.ClosedCasesInterestAmount ?? 0)
            });

var result = query
    .GroupBy(u => new {u.Country, u.CompanyId, u.CorporationId, u.Year})
    .Select(u => new 
    {
        Country = u.Key.Country,
        CompanyId = u.Key.CompanyId,
        CorporationId = u.Key.CorporationId,
        Year = u.Key.Year,

        RegisteredCases = u.Select(t => t.RegisteredCases).DefaultIfEmpty().Sum(),
        RegisteredCasesAmount = u.Select(t => t.RegisteredCasesAmount).DefaultIfEmpty().Sum(),
        ResolvedCases = u.Select(t => t.ResolvedCases).DefaultIfEmpty().Sum(),
        ResolvedCasesAmount = u.Select(t => t.ResolvedCasesAmount).DefaultIfEmpty().Sum(),
        ActiveCases = u.Select(t => t.ActiveCases).DefaultIfEmpty().Sum(),
        ActiveCasesAmount = u.Select(t => t.ActiveCasesAmount).DefaultIfEmpty().Sum()
    })
    .ToList();

i think Country and CorporationId must be same for grouped records based on CompanyId and Year, so i was included them in group by, to use in Select