在LINQ查询中使用Sum函数

Question

您可以缩短以下记录吗？

我想直接在“选择”中获取总和

var res = (from PR in context.TblPremium
           join P in context.TblPolicy.Where(p => p.ValidityTo == null) on PR.PolicyId equals P.PolicyId
           join R in context.TblReporting on PR.ReportingCommissionID equals R.ReportingId
           join O in context.TblOfficer on P.OfficerId equals O.OfficerId
           where (PR.ReportingCommissionID != null
                && (PR.PayDate >= minDate && PR.PayDate <= maxDate)
                && PR.ValidityTo == null
                && O.Code == model.enrolment_officer_code)
           select new
           {
               Commission = (R.CommissionRate == null ? 0.00M : R.CommissionRate) * PR.Amount,
               PR.Amount
           })
           .ToList();

var c = res.AsEnumerable().Sum(x => x.Commission);
var a = res.AsEnumerable().Sum(x => x.Amount);

response = new { Commision = c, Amount = a };