Question

In the following code for finding sum of Rate column in the DataTable dt:

dt.Compute("Sum(Convert(Rate, 'System.Int32'))");

In this is it possible to assign group by clause like SQL Inn order to get Sum based on a value in another column of the same dt Fo eg:

----------------------------
Rate | Group  |type
----------------------------
100  | A      | 1
120  | B      | 2
70   | A      | 1
50   | A      | 2
----------------------------

I just wanna to get.

Sum A=170(type-1) SUMA=50(type-2) an Sum B=120(type-2)

Ref: I got ans in my previous question in single column case
Group by in DataTable Column sum.

Answer 1

You can group by an anonymous type:

var result = from r in dt.AsEnumerable()
             group r by new { Group = r["Group"], Type = r["Type"] } into g
             select new { Group = g.Key.Group, 
                          Type = g.Key.Type, 
                          Sum = g.Sum(x => Convert.ToInt32(x["Rate"])) };

foreach (var r in result)
{
    Console.WriteLine("Group {0}, Type {1}, Sum {2}", r.Group, r.Type, r.Sum);
}