C# DataTable GroupBy/Aggregate

Hi, I need code to make this work I have the following code that I use to group Amounts in "Value", buy the Reference in "Account#" . // GROUP AND SUM THE VALUE COLUMN var result = (from row in [login to view URL]() let sup = [login to view URL]<string>("Account#") group row by new { sup } into grp select new { Supplier = [login to view URL], Advance = [login to view URL](r => [login to view URL]<decimal?>("value")), }).ToList(); var dt_docDAY01_GROUPED = new DataTable(); [login to view URL](new DataColumn[] { new DataColumn("Account#"), new DataColumn("DAY01"), }); foreach (var grp in result) [login to view URL]([login to view URL], [login to view URL]); But the above code wont work for my current project. I have a Reference in column 1. "Ref", and days of the month "DAY1" through to the corresponding days off the month be it "DAY28"/"DAY30"/"DAY31" etc. Example of first 3 day here.... (random example data) REF | DAY1 | DAY2 | DAY3 | A | 1 | | | C | 9 | | | D | 1 | | | F | 6 | | | G | 5 | | | A | | 2 | | B | | 3 | | C | | 4 | | D | | 5 | | F | | 6 | | H | | 7 | | B | | | 3 | M | | | 4 | C | | | 5 | G | | | 6 | I | | | 7 | J | | | 8 | I need it to be grouped to give the following result. The code needs to be dynamic to allow for more or less days 1 through to 31 etc. Example grouped below.... (From above random example data) REF | DAY1 | DAY2 | DAY3 | A | 1 | 2 | | B | | 3 | 3 | C | 9 | 4 | 5 | D | 1 | 5 | | F | 6 | 6 | | G | 5 | | 6 | H | | 7 | | I | | | 7 | J | | | 8 | M | | | 4 | This project is to provide code to dynamically allow for up to all 31 columns, or any better code i can use. thank you