How to get multiple sums that are subqueries - entity-framework

Question

Im using Linqpad to test out my EF query and I cant seem to get my end result to include a few extra columns that represent sums of a field based on different conditions
StorePaymentInvoices table contains a FK over to CustomerStatementBatchPayments. So I need to sum the CustomerStatementBatchPayment.net field if there is a corresponding value in StorePaymentInvoices
Getting the sums is turning out to be a real mess. Any suggestions?
Sometimes what is hard to do in one statement, ends up being easier done in multiple steps.
var retval = (
from a in CustomerStatementBatches
join b in CustomerStatementBatchPayments on a.ID equals b.CustomerStatementBatchID into grp1
from c in grp1
where a.CustomerStatementID == StatementId
group c by c.CustomerStatementBatchID into grp2
from e in grp2
select new {
StatementId = e.CustomerStatementBatch.CustomerStatementID,
BatchId = e.CustomerStatementBatchID,
Applied = CustomerStatementBatchPayments.Where(csbp => !StorePaymentInvoices.Select (pi => pi.CustomerStatementBatchPaymentID ).ToList().Contains(e.ID)).Sum (csbp => csbp.Net )
}
).ToList();
retval.Dump();
[ UPDATE 1]
This is what Ive done to get the "conditional" sum values and I seem to be getting the correct numbers. The resulting SQL that it generates is kinda ugly, but executes in < 1 second.
var retval1 = (
from a in CustomerStatementBatches
join b in CustomerStatementBatchPayments on a.ID equals b.CustomerStatementBatchID into grp1
from c in grp1
where a.CustomerStatementID == StatementId
group c by new { a.CustomerStatementID, c.CustomerStatementBatchID} into grp2
from e in grp2.Distinct()
select new {
StatementId = e.CustomerStatementBatch.CustomerStatementID,
BatchId = e.CustomerStatementBatchID
}
).ToList()
.Distinct()
.Select(a => new
{
StatementId = a.StatementId,
BatchId = a.BatchId,
AppliedTotal = (from b in CustomerStatementBatchPayments.Where(r => r.CustomerStatementBatchID == a.BatchId)
join c in StorePaymentInvoices on b.ID equals c.CustomerStatementBatchPaymentID
group b by b.CustomerStatementBatchID into g1
from d in g1
select new{ Total = (decimal?)d.Net}).DefaultIfEmpty().Sum (at => (decimal?)at.Total ) ?? 0.0m,
Unappliedtotal = (from b in CustomerStatementBatchPayments.Where(r => r.CustomerStatementBatchID == a.BatchId)
.Where(s => !StorePaymentInvoices.Any (pi => pi.CustomerStatementBatchPaymentID == s.ID ) )
select new{ Total = (decimal?)b.Net}).DefaultIfEmpty().Sum (at => (decimal?)at.Total ) ?? 0.0m
})
.ToList();

Answer 1

Try this
from a in db.CustomerStatementBatches
join b in db.CustomerStatementBatchPayments
//.Where(i => ...)
.GroupBy(i => i.CustomerStatementBatchesId)
.Select(i => new {
CustomerStatementBatchesId = i.Key,
SumOfPayments = i.Sum(t => t.Net)
}
)
into tmp from b in tmp.DefaultIfEmpty()
on a.CustomerStatementBatchesId equals b.CustomerStatementBatchesId
select new
{
StatementId = a.CustomerStatementId,
BatchId = a.CustomerStatementBatchId,
Applied = ((b == null) ? 0 : b.SumOfPayments)
}