来自数据表的具有空记录C#的Linq完全外部联接
有人能帮忙吗?我需要在Extn_In_Call_Records=Extn_Number上返回一个表,如果任何一方不匹配,仍然返回一个计算,就像SQL完全外部联接一样。我已经花了几个小时看这个,但无法让它工作!!如果我删除联合,我可以让下面的代码工作,但它只返回匹配的结果。正在从MYSQL填充Datatable。任何帮助都会很好来自数据表的具有空记录C#的Linq完全外部联接,c#,linq,C#,Linq,有人能帮忙吗?我需要在Extn_In_Call_Records=Extn_Number上返回一个表,如果任何一方不匹配,仍然返回一个计算,就像SQL完全外部联接一样。我已经花了几个小时看这个,但无法让它工作!!如果我删除联合,我可以让下面的代码工作,但它只返回匹配的结果。正在从MYSQL填充Datatable。任何帮助都会很好 //Full Table DataTable fullext = new DataTable(); fullext
//Full Table
DataTable fullext = new DataTable();
fullext.Columns.Add("Extn_In_Call_Records", typeof(string));
fullext.Columns.Add("Total_Calls", typeof(int));
fullext.Columns.Add("Extn_Number", typeof(string));
fullext.Columns.Add("Phys_Switch_Name", typeof(string));
//End Full Table
try
{
//Full Result
var result = from callrc in callrecdt.AsEnumerable()
join physex in physextns.AsEnumerable()
on callrc["Extn_In_Call_Records"] equals physex["Extn_Number"]
.Union
from physex in physextns.AsEnumerable()
join callrc in callrecdt.AsEnumerable()
on physex["Extn_Number"] equals callrc["Extn_In_Call_Records"]
select fullext.LoadDataRow(new object[] {
callrc["Extn_In_Call_Records"],
callrc["Total_Calls"],
physex["Extn_Number"] == null ? "" : physex["Extn_Number"],
physex["Phys_Switch_Name"] == null ? "" : physex["Phys_Switch_Name"]
}, false);
result.CopyToDataTable();
fullresult.DataSource = fullext;
结果见
Extn_In_Call_Records Total_Calls Extn_Number Phys_Switch_Name
null 20 0 Hospital
null 310 1 Hospital
4 132 4 Hospital
2004 null null Hospital
2006 2 2006 Hospital
根据,执行完全外部联接的最简单方法是合并两个左联接。LINQ中的左连接(使用扩展方法语法)采用以下形式:
var leftJoined = from left in lefts
join right in rights
on left.Key equals right.Key
into temp
from newRight in temp.DefaultIfEmpty(/* default value for right */)
select new
{
/* use left and newRight to construct the joined object */
}
在您的情况下,您希望执行以下操作:
// initialize some default elements to use later if
// they're of the same type then a single default is fine
var defaultPhysex = new {...};
var defaultCallrc = new {...};
var left = from callrc in callrecdt.AsEnumerable()
join physex in physextns.AsEnumerable()
on callrc["Extn_In_Call_Records"] equals physx["Extn_Number"]
into temp
from physex in temp.DefaultIfEmpty(defaultPhysex)
select new
{
// callrc is accessible here, as is the new physex
Field1 = ...,
Field2 = ...,
}
var right = from physex in physextns.AsEnumerable()
join callrc in callrecdt.AsEnumerable()
on callrc["Extn_In_Call_Records"] equals physx["Extn_Number"]
into temp
from callrc in temp.DefaultIfEmpty(defaultCallrc)
select new
{
// physex is accessible here, as is the new callrc
Field1 = ...,
Field2 = ...,
}
var union = left.Union(right);
请参阅(有关LINQ中的一般“外部”概念),并感谢您在这方面的帮助,但仍在努力使其正常工作。。。任何帮助都会很好。DataTable physextns=新DataTable();外部填充(物理性)//下表格式//(“公司名称”)/(“物理开关名称”)/(“外部编号”)数据表callrecdt=new DataTable();callrec.Fill(callrecdt)//下表格式//(“开关名称”)//(“Extn_In_Call_Records”)//(“总催缴股款”)//(“谈话时间”)//(“总成本”);