LINQ GROUPBY和带有Dapper的SUM可以实现吗？

我要实现的是每天计算利息[DailyLoanCalculation]，并在月底获得每个帐户的总计，并保存在[总利息]表中。每个月都会发生同样的事情

我有一个表DailyLoanCalculation，其中每天的每一天都要计算我的每日利息。我已经能够实现这一目标。

    DailyLoanCalculation table          
Day    Account No   Loan     interest Amount Per day    
1         12345     3000       150  
1         23456     1000       50   
1         43567     2500       125  
2         12345     3000       150  
2         23456     1000       50   
2         43567     2500       125  

    Total-Interest Table            
Day Account No  Loan   Total Interest  Total    
30  12345       3000    300            3300
30  23456       1000    100            1100
30  43567       2500    250            2750

现在要实现[总利息]中的问题。 这是我一直努力但无法前进的东西

 //Calculate the EndOfMonthDailyInterestCalculation
        public void EndOfMonthDailyInterestCalculation()
        {
            IEnumerable<DailyInterest> loans = null;

            using (var conn = new SqlConnection(ConnectionString))
            {
                conn.Open();

                loans = conn.Query<DailyInterest>("Select * from DailyInterest where BackgroundMonthly is Null");
                if (loans.Count() == 0) 
                {
                    return;
                }


                var TotalEachLoanInterest = loans.GroupBy(x => x.LoanAccountNo).Select(g =>g.Sum(x=>x.AmountPerDay));

**//I can go further at this point**

                if (TotalEachLoanInterest.Count() == 0)
                {
                    return;
                }
                else
                {
                    foreach (var loan in loans)
                    {

                        var SumOfInteretForTheMonth = loan.


                        var markDailyAsCalculated = new
                        {
                            amountPerday = loan.AmountPerDay
                        };


                    }
                }
            }
        }

如果有更好的解决方法，请帮帮我 谢谢