Question

Some serious brain power needed!! I have an issue where I am trying to calculate a price overcharge as days from two given date ranges. Basically I have an invoice line as below:

BillID     AccountID     BilledFrom        BillTo      Price
 34         3456         10/10/2012       10/12/2012    86p 

I then have a pricing matrix which can is:

AccountID      EffectiveFrom       EffectiveTo     Price
 3456          09/09/2009          10/11/2012      86p
 3456          11/11/2012          20/11/2012      56p
 3456          21/11/2012          10/12/2013      24p
 3456          11/12/2013           null           18p -- null never expires

Currently the initial price is taken where the BillFrom date is between EffectiveFrom and EffectiveTo dates and billed per days. Now I want to work out the overcharging from the bill as you can see that the BillTo date exceeds the EffectiveTo date for the 86p line. So there is a period of 1 month where the customer has been overcharged as line 2 or the pricing should kick in. I need a function either in SQL or C# which will outcome:

OverchargeID    type      BillID       Reason       Days     Price
    1          Credit      34       PriceChange      10        36p       (86p-56p)
    2          Credit      34       PriceChange      19        64p       (86p-24p)

I will be dealing with 56000 records Which could have up to 10 price ranges. I have the below code to work it server side but it is not practical at all and takes around 10 minutes. Any solutions or amendments to this code would be appreciated.

foreach (InvoiceOverchargePriceChange_SelectResult line in result) {

            //Get the invoiceLineRecord
            InvoiceLine invoiceLine = _dataContext.InvoiceLines.Where(m=>m.InvoiceLineID == line.InvoiceLineID).FirstOrDefault();


            // get the prices for each line
            List<Pricing_SelectResult> prices = ctrl.Select(line.AccountID, null, null, null, null)
                                                    .Where(m=>m.BillingMethodID == line.BillingMethodID)
                                                    .OrderByDescending(m=>m.EffectiveFrom).ToList();

            // if the price count is greater than 1 then need to check if overcharges occurred
            if (prices.Count > 1) {

                DateTime date = new DateTime();
                int days = 0;
                decimal charge = 0; ;
                for (int i = 0; i < prices.Count(); i++) {
                    days = 0;
                    charge = 0;

                    //if it goes in we found our price that we used
                    if (invoiceLine.BillFrom >= prices[i].EffectiveFrom && prices[i].EffectiveTo != null) {

                        date = invoiceLine.BillTo;
                        if (prices[i].EffectiveTo == null) break;
                        //check the Bill to date does not exceed the effective To date, if it does go in
                        while (date >= prices[i].EffectiveTo) {



                            if (date == invoiceLine.BillTo) {

                                //if its first go set the price
                                charge = prices.Where(m => date >= m.EffectiveFrom).FirstOrDefault().Price;


                            }

                            if (charge == prices.Where(m => date >= m.EffectiveFrom).FirstOrDefault().Price) {

                                //increment the days counter
                                days++;
                                date = date.AddDays(-1);

                            }
                            else {

                                //insert the days and price into db here...


                                //reset the days
                                days = 0;
                                charge = prices.Where(m => date >= m.EffectiveFrom).FirstOrDefault().Price;




                            }


                        }

                    }

                }

            }


        }

Thanks in advance

Answer 1

Try this…

 select 
      ROW_NUMBER() over (order by BillID, StartDate),
      case when (billprice>pricingprice) then 'Credit' else 'Debit' end,
      BillID,
      DATEDIFF(d, startdate,enddate)+1 as days,
      billprice-pricingprice
 from
 (
      select 
           BillID, 
           case when Effectivefrom>BilledFrom then Effectivefrom else BilledFrom end startdate, 
           case when isnull(effectiveto,GETDATE())<BillTo 
                then isnull(effectiveto,GETDATE()) else billto-1 end enddate,
           bill.price as billprice,
           pricing.price as pricingprice
      from pricing
     inner join bill
                on bill.accountid= pricing.accountid 
                and (billedfrom<isnull(effectiveto,getdate())) and (BillTo>Effectivefrom)
                and bill.price <> pricing.price 
 ) v