数据是被加载到经由OLEDB一个ado.net数据集的本地CSV文件。该表包含40列以上的发票明细。每一行都是发票中的一个单独的行项目,它可以由1到n行组成。LINQ - 基团/总和多列
该查询被用来组发票细节成每个发票单排,共计发票金额和平衡所致。
下工作,我尝试以确定: 是否有可能做到这一点在单个查询?
//group the invoices by invoicenumber and sum the total
//Zoho has a separate record (row) for each item in the invoice
//first select the columns we need into an anon array
var invoiceSum =
DSZoho.Tables["Invoices"].AsEnumerable()
.Select (x =>
new {
InvNumber = x["invoice number"],
InvTotal = x["item price"],
Contact = x["customer name"],
InvDate = x["invoice date"],
DueDate = x["due date"],
Balance = x["balance"],
});
//then group and sum
var invoiceTotals =
invoiceSum
.GroupBy (s => new {s.InvNumber, s.Contact, s.InvDate, s.DueDate})
.Select (g =>
new {
InvNumber = g.Key.InvNumber,
InvDate = g.Key.InvDate,
DueDate = g.Key.DueDate,
Contact = g.Key.Contact,
InvTotal = g.Sum (x => Math.Round(Convert.ToDecimal(x.InvTotal), 2)),
Balance = g.Sum (x => Math.Round(Convert.ToDecimal(x.Balance), 2)),
});
你可以把第一的GroupBy后立即选择,而不引入invoiceTotals的可变 – Uriil
可能重复的[组按多个列(http://stackoverflow.com/questions/847066/group-by-multiple-columns) – psubsee2003