需要一些严重的脑力！我有一个问题，我试图计算两个给定日期范围内的天数多收费用。基本上我有如下发票行：
BillID AccountID BilledFrom BillTo Price
34 3456 10/10/2012 10/12/2012 86p
然后我有一个定价矩阵，可以是：
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
目前，初始价格是在 BillFrom 日期介于 EffectiveFrom 和 EffectiveTo 日期之间并按天计费的情况下采用的。现在我想计算账单中的多收费用，因为您可以看到 BillTo 日期超过了 86p 行的 EffectiveTo 日期。因此，在 1 个月的时间里，客户在第 2 行被多收了费用，或者应该开始定价。我需要一个 SQL 或 C# 中的函数，这将产生：
OverchargeID type BillID Reason Days Price
1 Credit 34 PriceChange 10 36p (86p-56p)
2 Credit 34 PriceChange 19 64p (86p-24p)
我将处理 56000 条记录，其中可能有多达 10 个价格范围。我有下面的代码在服务器端工作，但它根本不实用，大约需要 10 分钟。对此代码的任何解决方案或修改将不胜感激。
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;
}
}
}
}
}
}
提前致谢